Safe Second Level Question

[Sambomom]

I'm making out my plans for building our C&C cage when the time comes and I'm planning on a second level. The second level will be 2x3 or 2x4 and if it's 2x3 there will be a little space where the cubes don't completely touch the ramp. There will still be the 6" coroplast there from lining the cage up there, but do I need more hight in the front there or will 6" be enough? I want to make sure it's ultra safe for them, no dive bombing piggies or anything getting hurt.
Thanks for your time,
Carol

[Jenni_Feathers]

Heee hee heee...dive bombing piggies thats funny well sorta I'd never want them get hurt but, anyway 6in humm I think that be a tad short I have the same prob and use 8in tall but all you would have to do is elavate it off the ground a bit so maybe like and inch or an inch and a half but small enough they cant go under.