A couple of weeks! Hell, I'm still trying to get the hang of it. *G* Many years ago, I used tortise shell picks taken from actual tortae; they were magic. Now I use the standard plastic ones made to look like tortise shell. I hold it with the sharpest corner aimed at the base of my thumb and pick with one of the rounder corners. I've also been playing a heaver pick and closer to the bridge lately.
Thanks for the thumbpick tip. I'll find some way to get hold of one and try it out. Failing that, we may be in Toronto sometime in late summer and I can check at The Twelfth Fret myself.
A man I studied with some years ago used to make his own picks. A toolmaker friend made him a punch and die device that worked rather like a bottle capper. The picks it made were roughly the size and shape of the Fenders but with three holes clear through the pick to aid in holding onto it. He would make picks from every stray piece of plastic he found just to see what materials were best. I still have one he gave me. It was made from a polyethelene waste basket and is just great on an electric for jazz.