I liked teaching them to do standing back tucks starting with it simple on a trampoline or tumbl-trak. From there, I like to add resistance in the form of 4 or 8 inchers. Two stacked up takes quite a lot of the bounce out of the bounciness and focuses on a harder jump.
This is what I used to get over the skill, but it could just be a mental thing. I was definitely strong enough when I started training them so it was more of a head issue.
I used to also set the rings at an appropriate height and do a jump and immediate fast skin the cat to land. They would placed at roughly the peak of my jump. However, this will take probably more ab strength that many cheerleaders lack when they " want " this skill.
Usually, I look at their ab and leg strength and determine if they any chance. The only other factor is the guts and correct technique of the set.
I've come across a figure of a 20% of their standing height when it comes to vertical leap power. I played around and was just noticing the difference betweens kids and their vertical leap numbers to skills like BHS and standing back. 10- 15% seems to be ok for enough for BHS. Personally, I'd like 25% for their standing back tuck. If they are 5 feet, they should vert leap 15" then or maybe 12". 12 sounds too low to me. I haven't really figured out how much ab strength they need. Bare in mind this is for a good standing back with good compression versus the often seen whipback, open tuck things I often see by cheerleaders.
I sometimes tend to flip flop between those tumbler and cheerleaders who want to tumble well and just tumble something. As long as there isn't a safety issue, I just give up on the tumble somethings. Their loss. If they want and show they have the dedication to tumble correctly and possibly big, then we can go the slow route vs the instant gratification tumble something route.