Primning/Fermentation issue on Barrel Aged Imp. Stout

So I have been thinking about what the best strategy will be to make sure a batch of beer carbonates but does not result in bottle bombs. Here are some details:

I was making an Imperial Stout aiming for an OG of 1.100 but I think my homebrew store gave me more than the 9lbs of DME that I requested because the OG ended up being 1.121. The recipe does include two 3.5oz bars of Lindts Chocolate added in the last 5 minutes of the boil and my software didn't account for how this would affect the OG, but I doubt it would raise it by .021 in a 5 gallon batch. Not having too mnay options, I pitched one packet of S-33 and hoped for the best.

Fermentation went slow and steady for about 1.5 weeks. It never seemed to be as active as some of my other high gravity beers, so I was surprised when I checked the gravity after 2 weeks that it was 1.035. It sat in the primary for another 2 weeks, and then I transferred it to a 5.5 gallon oak barrel. The gravity was still 1.035. I added a fresh packet of S-33, and now it has been in the barrel for 2 weeks. I plan on tasting it to see if there is enough oak, and also measuring the gravity Tuesday night. If there is enough oak, I am bottling that night.

I already plan on adding another packet of S33 into the bottling bucket. The question is, how much priming sugar do I use. For the stout, I don't need much carbonation, so the typical 5 oz for 5 gallon batch is way too much, I am worried that if I use too little that it won't carbonate at all. Also, with the ABV being at 11.4% before taking into account what it may hav gained in the barrel, it is already at the upper end of S33's tolerance. I am not expecting the gravity at this point to be much lower than the 1.035 when it went into the barrel.

Because I was not aiming for and 11.4%, is it a viable option to add some water to the batch at bottling in order to give the yeast a better chance? Or do I just use 2oz. priming sugar and hope for the best?

Thanks for reading this lengthy post and I appreciate any input.

i would add 3.5oz of priming sugar and i would skip new yeast addition, beer is fresh so there is still a lot of yeast, if you are afraid abv is too high for this strain then adding the same strain will not help much (abv still will be too high right) so it would make sense to add different strain (champagne) but again i dont think its necessary.
On the other note i would keep it longer in 2ndary, if oak tast is to your liking then transfer to glass and bulk age for 3-6 months and add fresh yeast before botteling.

this calc should aide in how much priming sugar you'll need. as for adding yeast at bottling, i do when i age a big beer for more than a few months just to be safe. it won't hurt the beer, and i just see it as a little insurance.

What do you think the extra aging time will do the chocolate, coffee, and maple syrup flavors? Will they diminish?

that i couldn't tell ya. i know with a beer like a RIS, aging helps the flavors develop and become more what you expect from a beer like that. you have a big beer there, and the aging will definitely benefit the flavors. in a beer like that, the age will also help blend the alcohol with the beer flavor, and produce a more rounded beer. i know that's a really vague way of describing it, but i hope that helps.