Shakes,

You need gobs of elevator travel along with power. It's actually not easy to tell which is the problem you are having not knowing the amount of throws you have and the engine/prop combo.

I know someone that has a big Yak that will do it with 50 degrees of elevator and a DA50 turning a 23X8 Mezjlik on a tuned pipe

I know another one with the same size Yak with a MVVS58 and a 24X10 NX but a little lacking in the elevator throws and he will get part of one turn and instant flat spin

I think the best plane I have ever flown for a KE spin is an Ultimate. My GP Ultimate with 45 degrees of elevator and a Brison 3.2 spins right around the wingtip (actually it looks more like it's spinning around the CG) and does it really quick to boot and it can be coaxed into this position from any number of starting positions. I beleive it's the short coupling of the plane is what makes it so easy to do with not much elevator throw