Finger on braid works great and reduces possibility of wind knots and increases casting distance. The only set back, the section of braid where it contacts the glove will wear. Mandating a change whenever fraying becomes visible. Or end of day even if fraying is not, rate of use dependent of course.
If you're using fluorocarbon (not necessary for GT casting IMHO) then, as little line or none in the spool to reduce wind knots. Like Mark, I have 2-3 turns of mono in the spool and the length of leader is dictated by rod length.
I tie my leader direct to the lure, and this length will allow me a few lure changes before all the mono is out of the spool. Little know fact that nylon leaders WILL weaken and deteriorate quite rapidly under UV. So it behooves us to change leader sooner than we think necessary.
I change my leader end of day or after 2 days if the usage if low and rod is kept out of direct sun.
Ben