I've been around the stunt scene for over 10 years but personally never had much interest in it....until this year...
I finally gave in and picked up a CRF50, put my 12 bar and handbrake and instantly addicted. Recently went out riding until my blisters on my hands popped and started to bleed...literally)
Starting on the 50 was absolutely the best thing I could have done, and cost efficient. While I obviously spent time blowing past the balance point often, the 12 bar would scrape and simply standing up would save the bike from dropping and nothing ever broke.
I went from no stunting to being fairly comfortable and consistant with my circle wheelies, and just picked up a new Z125 last weekend! Just waiting for the parts to arrive!
Moral of the rant, if you really want to have great progression, start small. You'll learn quickly how to f up with minimal damage to the bike AND wallet
For me, learning to not be scared was the main obstacle. Now that I know there's nothing wrong with a little loop out here and there, I've gained much more confidence and don't hesitate!
The faster the wheelie comes up, the slower you're moving and less change of damage. Trying to chase the balance point and increasing speeds is where people get hurt.