2.5 gallon boil to 5 gallon boils

I have been doing extract for some time now and have done several full boils using 2.5 gallon boil recipes. What modifications to the amounts do I need to do to keep the flavor profile close? I am doing a Karankawa Pale Ale from AHS.

Do I need to cut the amounts of hops and do I need to adjust the steeping grain time. What is the rule of thumb on this?

I plan on purchasing Brewsmith software shortly.

Recipe

steep 1 lb crystal 40 for 20 min @ 155 degrees
bring to boil, add 7 lb pale malt extract
bring to boil
Hops:
1oz Sorachi @ 60 min
1/2 oz Cluster, 1/2 Sterling @ 15 min
1/2 oz Cluster, 1/2 Sterling @ 5 min

help greatly appreciated

P. Spence

Most will chime in about cutting down on bittering hops but when I went full boil I went with the same amount based on some good advice from a member here. I tasted the beer when I transferred it to the secondary and it tasted great to me. The rest of the recipe should be the same. I followed the better extract brewing techniques from Brew Your Own magazine article I found online.