Why make a new thread for this?
I've made dozens of miniramps and quarterpipes and always draw elliptical transitions. For small ramps, it gives you a mellow transition that's easy to land tricks with a workable lip (gets it closer to vert). If you can find Neil Blender's Speed Freaks part, his backyard ramp is a good example (I wouldn't recommend making it that steep though). I'd be surprised if it's even 4' tall, but he can still lock into smith grinds.