full ring and 6-max are different games. I believe you would be better off just jumping to 25NL 6-max and keeping with what you know, then jumping in to 25NL full ring and have to adgust your game.

If you are playing more then one 10NL table you may want to consiter temperarly dropping down to 1 or 2 tables while you adgust.

You said you don't feel like your bankroll can sustain a straight jump into $25NL 6-max. You don't want to be playing scared when you move up, this will just make it harder. You may want to stay at 10NL and build your bank roll up a little more until you are more confident.