I agree that 2 inches of relfex is probably enough.
A bow I started once was long and very thin but I put in 5 or more inches of reflex. It was really hard to tiller, very unstable and pulled 120lb to get the tips 3 inches behind the handle! What looks like a little wood really does go a long long way with a relfexed Ipe/Hickory or Ipe/Bamboo bow.
My feeling is that Ipe does better as fairly narrow fairly deep bows. Where the Ipe gets thin and wide it can fail if the grain isn't great. My reflex deflex bow ended up with thin Ipe and I had failures along the grain where the limb was most stressed. Cured with binding but I think it shows that the bow could have been thinner, deeper and more mildly deflexed and reflex and probably performed better.
ADB. Pleased to hear that your wife can pulls a 50lb bow if she wants to. An Ipe 50lb bow will be a lot more slender than most other bows of the same draw weight. To put it another way, a non gender sensetive way, what looks like a childs bow, a small slender bow can in fact be of suprisingly heavy draw weight. Is this ageist now?
Best of luck with your bow Eli. I think you will like it a lot when you have finished it.
Mark in England