If it doesn't cause hip rocking, saddle irritation or hyperextension of your leg issues then this is fine. I'm guessing for Tri riding it won't. I like good leg extension but the truth of the matter is, its not really a more powerful position. Whether your hip angle ends up being 150 or 155 isn't going to provide a more powerful stroke. Best to try it at 150 or even a little less for a couple weeks, then 155 (this should correspond to heel on the pedal as you mentioned).

Having said this, I don't typically ride Tri so I defer to anyone who has more experience riding Tri on this question.

This "heel" method gets me to exactly 145 degrees of extension. I have ridden with a larger angle but find I'm more comfortable on the adamo for longer periods of time with a slightly lower saddle....