Should I stop scrimmaging as a whole? Or just start my bench?
You don't need to do either. It is possible that you can start your starters in the league games, while your backups get some minutes. Barring injuries or foulouts, your starters should have enough minutes after a second league game. As a result, some (or all) of your backups may need more minutes.
My rule is that if a backup needs more than 15-20 minutes, I start him in the scrimmage and put a scrub as the backup. If they need less, then I put him as the backup. The general consensus is to play your players 50-60 minutes per week for the best GS. Hope this helps.