I have had a couple of 35 Whelen AI's over the past 25 years. the usual loads for a standard 35 Whelen are a good place to start. Your max load will be only about 2-5 grains more than the standard and the velocity increase will be about 50 - 75 FPS; hard to detect without some prolonged chronograph work and careful statistical analysis. The main reason for going "AI' is the improved case life. I'd suggest necking up your brass to 375-40 caliber then sizing down to get precise headspacing for fire-forming, particularly if using 30-06 brass. I prefer getting factory Remington 35 Whelen brass. If you use other brass, be sure to anneal the neck/shoulder area before final forming or it will soon crack.
Except for "real' zeroing/hunting loads, I use as 38/357 die to neck size only (being careful to no bump the shoulder). The bolt can be a bit snug to close, but it works fine for light practice/ beginner loads. My eldest son shot his second deer at age 8 with a 200 gr Hornady roundnose loaded to 2200 fps (Reloader 7 was the powder if I recall) with this technique.
I like 35 cal rifles. They are reliable on game and usually very accurate with jacketed 357 pistol bullets. My 35 Whelen AI's have not been picky about bullet weights. they had Shilen barrels with 1:12 twists.