Pe:

The locking taper ( 10 degree ) was a deliberate choice on the four stroke engines, it gives that added bit of prevention against throwing a prop. On a two stroke engine with its lower tendency to backfire the non-locking tapers of 17 or more degrees angle are fine.

With my puller I've never had to use any heat - you may have noticed it's rated at 5000 pounds screw pressure - but it is a lot more money than could be justified for casual use.

Bill.