im not too sure on how different it will be from standing/trampoline and on bocks, I'd assume as long as you get the technique right on the back flip then the majority of your momentum should be going directly to the ground and so be relatively stable, and given that you are able to see the floor as you come to land, it shouldnt be too much of a leap (although don't take my word for that)
I plan to use the next two weeks to practice front flips from standing (using an old mattress as a makeshift crash pad
) and watching various videos explaining the movements in detail.
I'll attempt to video my first try on stilts so we can all enjoy me face planting the floor