As you mentioned you might be able to get away with less wave in the unit hair if you keep your growing hair shorter. Just going to have to try it and see what works out. You might want to order something a little curlier than you would prefer for your first unit and adjust accordingly on subsequent orders. Once you get a couple of these in your hands and start tweaking them you will figure out pretty quickly what will work and what won't, but it's better to err on the side of caution for your first order.

Good luck, hope to see pics when you get your first unit!