Belgian Dark Strong Feedback

I’ve been putting together a recipe or a Belgian Dark Strong that I’ve wanted to do for a while and have just been waiting for the right time to jump on it. I’m going for something with a nice solid malt backbone and a very clean hop bitterness and minimal flavor/aroma. I’m looking for the yeast to really come through with some good dark fruit character. Here’s the recipe I’ve put together for a 5.5 gallon batch, any commentary is appreciated:

Grains:
Belgian Pale Malt – 14 lbs
Carapils – 1 lbs
Belgian CaraMunich – 12 oz
Belgian Special B – 12 oz
Belgian Biscuit – 12 oz

Single Infusion mash with 23.5 qt of water, 153 F for 75 min
Batch Sparge with 3.75 gallons of water

Boil Size – 7 gal
Boil Time – 60 min

Hops:
Warrior, 15 %AA @60 min
Styrian Goldings, 5.5 %AA @20 min

Yeast:
WLP545 with large (3L) starter
Ferment starting at 68F, raise temp over time to end around 75F

Add 3 lbs of Amber Candi Syrup in 1 lb increments starting at the height of fermentation. This is a homemade candi syrup made from 2 lbs of sugar.

Efficiency: 65%
OG: 1.090 (adjusted for syrup additions, 1.075 initially)
FG: ~1.015
IBUs: 30
Color: 27
ABV: 10.4%

I normally keg my beers, but I'm leaning towards bottle conditioning and aging this one for a while. I've never bottled one this strong, so I'm wondering if y'all think it will be good to bottle as is with normal amounts of priming sugar, or if I should pitch some more yeast at bottling.

I'd say that grain bill looks good. You could consider using some flaked wheat or even oats for mouthfeel and head retention instead of just Carapils. I've only recently decided that for a dark strong, the Belgians are really right that the key flavor contributions are from sugar. What's so interesting about many of the authentic dark strongs (and dubbels) is that they have a very deep flavor, but it's not exactly a "malty" flavor (the way that, say, doppelbock might be); it really is a caramel, dark fruit, toasted marshmallow profile. If you make a maltier base (by using a lot of Munich, for example), you can muddy that. So I think you're going the right way with keeping the grain bill pretty simple.

But I would make sure that your homemade amber syrup has the right sour/bitter, roasted marshmallow flavor that you need to make a deep beer. If it is lacking, you could add a pound of commercial (D180) syrup too.

If you want minimal hop flavor and aroma, you could cut the styrian goldings altogether. I don't think it will be harmful, though. Long aging will tend to diminish whatever you do on the hop front.

I have not personally brewed with 545, so I can't add too much there. I would say that you should probably let the temperature free rise; in my experience, that's important for getting the (high) attenuation necessary for the style. But if you're operating under true temperature control, 75F is also a good final target.

If you bottle condition this beer, you can definitely pitch a small amount of yeast (anything will do) at bottling. I would do that if you leave it in primary/secondary for at least 6 weeks (10.4% ABV is rough on the yeast). Priming sugar should be normal as long as you get proper attenuation to begin with and aren't pitching something odd (e.g. 3711, or brett) to carbonate.

Just some random thoughts:

1.) Carapils for a Belgian Dark Strong?
2.) Add your Candi Syrup at flameout and make sure it's dissolved in solution, might end up at the bottom of the fermenter otherwise.
3.) You may get away with bottling as-is if you don't cold condition before bottling; but to be safe I would add new yeast when bottling a large, alcoholic beer.
4.) Consider splitting your Pale Malt 75/25 or 50/50 with Pilsner.

Thanks for the input.
I chose to use carapils mainly for the head retention, although I think I may sub out half of it for some flaked wheat as suggested, a full pound of one may be a bit much upon second glance. I was planning on adding the syrup late because the yeast supposedly gets lazy if you feed it too much simple sugar up front and tends to under attenuate, maybe I can split it up and add some of it at flameout, and some during primary with a gentle stir. I had also wondered about mixing the pale and pilsner malt, or even going all pilsner, but I wasn't really sure I'd be able to tell the difference between the malts one way or another. And I'm thinking this beer will spend a fair amount of time aging in bulk, so I'll plan on pitching more of the same yeast at bottling to be safe.

With this kind of gravity, if you also go with the typically high levels of carbonation, you'll have no problems with head retention.

Ah good point I hadn't thought of that yet. The carbonation levels I had overlooked... what sort of levels should this style be carbed up to, I have no idea?

Depends upon if you're bottling or kegging, in the end. Bottles, I'd shoot for 2.5-3 volumes, keg 3-3.5. I've had bad luck with bottles over 3 volumes, so I don't even try anymore.

Thanks for all the great feedback. I picked up the supplies for this today. I've got my first starter going on the stir plate now and I'll be stepping it up throughout the week to hopefully brew next weekend. I ended up going with some flaked wheat instead of all carapils (technically Belgian caramel pils), and I also went with 75/25 mix of pale/pilsner malt.

I wanted to give a quick update to how this has been going. So I brewed this up on 8/22, ended up with an OG of 1.086 before the syrup so I was quite pleased. It's been fermenting away between 66-68 for 5 days now, I added some of the syrup two days ago, and just added the rest this morning. This yeast is hungry, it's been going like crazy. I checked the gravity and it's dropped from an adjusted 1.100 to 1.020 in this time and shows no sign of slowing down yet. I'm going to let the temp rise up to room temp now which is about 77 and let it finish up and then hold it here for another 3-4 weeks before bottling. I'm shooting to have it finish around 1.010, although my mash temp got a little high on me at 156, so we'll see if it stalls out here pretty soon. Biggest beer I've made to date, 11.8% would be awesome, it doesn't taste excessively alcoholic yet, the low temps definitely kept any fusels at bay, and it's only mildly estery, lots of rich maltiness and bread flavors though. I can't wait to have this finish, it's shaping up to be a big winner.