practice -- what QQ suggested -is what I tried to explain in previous posts above - the plane requires far less control input- as there is far less load on surfaces
Bad news - simply finding an ideal switch position--is about a hopeless task-
you are best of learning to apply a quick input and release it -
there is no ideal "setup"--
If you can't get the hang of it - this maneuver may be the one case where you use a snap button -(I refuse to use them).
Up line -- start with enough speed -then apply full power and try best combos of throw (different quick applications of stick)
do not reduce power on the upline snap -this will kill it quicker than anything .