What do you think of this barley wine recipe?

So this is kind of a take on brewpastor's barley wine recipe found here
https://www.homebrewtalk.com/showthread.php?t=26724

I just got some all grain equipment mainly a 10 gallon cooler mash/lauter ton. So I am going to be mashing for the first time, so expect my efficiency to suck. I modified the recipe to fit my equipment and what was available and this is what the guy at the lhbs came up with.

7 lbs american 2 row pale
1 lb munich
2 lbs flaked rye
1 lb crystal 60
.5 lb crystal 90
3 lbs muntons light dme

white labs California ale yeast
4 oz northern brewer plugs
4 oz perle plugs

Now the guy at the store said this would be a good gravity for 4 gallons however I forgot I wanted to add some maple syrup brown sugar or both. I have a 12 fl oz bottle of maple syrup which I want to use and also brown sugar however I can't seem to find a good formula to calculate my gravity once its all said and done. My assumption is that since the gravity was good before, if I want to add the maple syrup and brown sugar I can go up to 5 gallons and be ok.

So I guess my questions are can someone point me in the direction of a good formula for calculating gravity. Also, what do you guys think of the recipe, this is a little ambitious for a second batch but what the hell its what I want to drink so its what I'm gonna make.

I also have a thread about my ****ty starter here
http://homebrewtalk.com/showthread.php?t=67670

Thanks

I applaud you for jumping into a barlywine so early!

What do you mean exactly about "can someone point me in the direction of a good formula for calculating gravity" Are you wondering how many points you'll get from the maple sugar and the brown sugar??

Good to go for a big batch so early. I wouldn't add either the brown sugar or maple syrup to a barleywine. That does seem like a bit much for hops too. I'm assuming you are going to use the NB for bittering and the Perle for flavor/aroma? I know with the higher alcohol levels you can have higher IBU's, but that does seem a tad much. Just my opinion, though. I've made a barleywine before and used 2 ounces of NB for bittering (boiling for 90 minutes) and 2 ounces of a low-alpha hop for flavor/aroma.