"non" knuckle to Jack Regulation

[Jon Page]

Just treat the front edge of the molding as if it were the front of a 
standard core.
Position the jack top midway of that edge, depending on the breadth of the top.

An easy check to see if the jack sufficiently under the knuckle is to 
apply light
downwards pressure on the hammer as you press down the key all the way to
Let Off. If the jack doesn't slip out (cheat) it is OK. You can find 
the forward limit
this way but keep it back a little further under the knuckle to 
insure repetition.
-- 

Regards,

Jon Page