[Ian]

This is how i do it...

Start with a RH, make sure you have the timing perfect and its nice and steady, not turning, dead strait.

Start to add power, depending on the plane and its power to weight ratio, you might or might not need full power, controll movements i usually find have to be reduces. This first half is more like a tight rolling loop, as you arnt really in a harrier attitude.

As you get to the top, start to recude power, and elongate the top of the loop so it is longer. when you get to say, 5/8th of the loop, idle the power, and really slam those controlls to the sides of the TX, make sure you get the plane into the horizontal as quickly as possible, sorta like a rolling elevator. Keep it at idle 'till you want to pull out, then add power and adjust controlls to go into a rolling harrier again. on the flip over to horizontal rolling elevator, you might need blasts of power to keep the ailerons going, as they do struggle.

Also, my 2m yak with a 22" prop strugles to do it to the right due to the torque, but to the left its a breeze.

hope this helps
Ian