SNPA recipe help

I'd like to try an extract version of a Sierra Nevada Pale Ale recipe that I came across on the northern brewer forum. Trouble is, I also want to do a late extract addition of the DME. Can anyone offer suggestions on how I should modify the hop schedule for a late extract addition version of the following recipe?

Beer Fan's
OG: 1.053
Color: 11.9 SRM
Bitterness: 37.0 IBU

BeerTools (Don's extract alteration)
OG: 1.053
Color: 12.82 SRM
Bitterness: 37.5 IBU


1.0 lb. Crystal Malt 60°L

5.5 lbs. Muntons Extra Light DME

.5 oz. Yakima Magnum (Pellets, 13 %AA) boiled 60 min.
.5 oz. Perle (Pellets, 9 %AA) boiled 30 min.
.8 oz. Cascade (Pellets, 5.50 %AA) boiled 10 min.
2 oz Cascade (Pellets, 5.5% AA) aroma. 0 min.

Yeast : White Labs WLP001 California Ale


This recipe was created assuming a 3 gallon boil. I could probably go up to 3.5 gallons.

Bump...

Maybe just take the hops down by about a third?

I wouldn't. That recipe says it's got 37.5 IBUs, but the only way it does is if it's a full boil. (I get 30 with a partial boil) If you add the extract late in the boil and do a 3.5 gallon boil, it'll more closely approximate the full boil. If you add 3 pounds at the beginning, and 2.5 pounds with 15 minutes left, it looks like 38 IBUs, using the same exact recipe.

how many vials of yeast? Starter? also, if doing a full boil, what kind of adjustments to the recipe??
Thanks!