Former MTT specialist starting playing SHNL

This is the deal, ive been starting to play short handed NL at NL100 although i have BR for much higher levels but i want to gather exp and get comfortable at the new games before i move up and was wondering if you have any suggestions on how many hands i should play at that level before i can say with confidence that i am in fact a winning player and move up, 20K, 50K, 80k?

to prove if your a winning player, i'd say 50k.

For a more realistic winrate @ that level... probs 100k

ok, just want to be sure that im not the donkmaster 5000 special edition, so i can move up and have confidence in my game