Modifying an extract barley wine recipe - am I courting disaster?

I'm planning to brew a barley wine based on this recipe: http://beerrecipes.org/showrecipe.php?recipeid=400

I'm making the following changes:

1. 3/4 lb. brown sugar and 3/4 corn sugar instead of 1.5 lb corn sugar. I'm guessing the flavor will be a little darker and more complex this way.

2. No Sparkeloid. I don't have any experience with Sparkeloid, but the brewshop dude insisted it was an unnecessary clarifying agent. I'm going to use the indicated 2tsp Irish Moss, and don't care about absolute crystal clarity.

3. 2 11.5g packets Safale US-05 dry ale yeast instead of the unspecified quantity of champagne yeast. Also a recommendation from the brewshop.

Am I getting myself into trouble here? Will it really take 7 months to ferment completely? Any other thoughts on the recipe?

I think those are all great calls. I think 2 months in primary should be sufficient. 7 months is a LONG time to leave a beer on the lees.