You might want to invest 25 dollars in the Promash program. Skimming the Promash website last night, I saw where the program has a feature that will calculate hops degradation. I think that is what you need to find the optimum date for the IPA. Some Promash users could confirm that.
And YES, I would say a practice batch or two would really help as well. Practice getting a nice clear IPA as well as getting the taste you want. Clarity isn't a big issue with a stout, but I would even make a trial run with it too.
I racked my SNPA clone today after two weeks in the primary, and it isn't nearly as hoppy as I had feared. I guess adding too much hops in a stupor, didn't really hurt, because I only did a partial boil. There is a big difference between a partial and full boil when it comes to hop bitterness.
Best of luck! I'll be watching for reports of your efforts....