[TimB_Stoke]

If I understand you right, you're using an approach I occasionally use for tournament play. Example:

1. Win 2 in a row at whatever level I have 20 buyins for
2. Play next level
3. Repeat 1 & 2 until I lose a tourney (always making sure the profit from one level more than covers the buy in for the next level)
4. As soon as I lose one, I drop back to whatever level I currently have 20+ buyins for.

This way, a typical days play could go (assumming 6 handed SNGs with 70/30 payout):

Start $25
$1+.10 Win $4.20 - Balance $28.10
$1+.10 Win $4.20 - Balance $31.20
$3+.30 2nd $5.40 - Balance £33.30
$1+.10 Win $4.20 - Balance $36.40
$1+.10 Win $4.20 - Balance $39.50
$3+.30 Win $12.80 - Balance $49
$3+.30 Win £12.80 - Balance $58.50
$5+.50 Lose - Balance $53
$1+.10 Lose - Balance $51.90

Repeat until rich/broke.

It seems to be fairly effective for tournament games so far, in that it lets you maximise on winning streaks, as long as you have the discipline to drop back to your starting level when you lose. I wouldn't try it in ring games myself - the larger swings will eat your bankroll far more quickly.