Max Value:
A flat bettor and a percentage bettor can be two different styles. A flat bettor could be wagering a flat dollar amount per game or a flat percentage of their bankroll per game.
As for me, I identify my wagers by units which are equivalent to a percentage of my bankroll with an adjustment as the bankroll increases or decreases 20%. I rate my plays 1*-5* which is equivalent to 1%-5% of my fluctuating bankroll.