the shorter the chainstay, the easier it is to pull the bike up on back wheel tricks

but at the same time it can flip out faster when pulling a manual.

Some of today's street frames have as short chainstays as flatland frames.

Seat tube angles don't have a lot of importance, specially if you run a low seat.

I'm wondering the same.
I ride a G9. I find its pretty good. Not the shortest Chainstays.

I'm seen some small talk here about bike setup.
like. Having lowering bars for a bit more response when pulling the bars towards yours. Shorter distance or something?

It seems alot of the guys riding back wheel all have some different setups. so it could be more to with having the frame to suit your body, height and such

that should just be pains from practicing, Your putting to much tension on your arms from pulling up on the peg wheelie, you have to reach the balance point and relax your arms more.

I think less than 13.25'' is easy to pull up the back end up and do lot of spinning/turbine/pumping tricks in tight circles..
For longer than 13.25'' the bike is more stable in many tricks but you will get tired faster.
you have to find what is better for you.. I had many years 13.5''then went to 13.4'' and now its around 13.25''
if you have a 25-9 gear the 13.25''is almost standard in most frames..add or take off a half link and you are somewhere there if you thin 13.25 is short add a half link and it will go around 13.375 thats is good also...
shorter bars are faster for lot of tricks but you use more power also while taller bars are lighter to keep the back end up..the biggest secret is to keep practising at whatever you have and then you ll find what fits you better in your riding style.cheers