I've played a lot of LCD the last few seasons. With your experience you probably won't be surprised by y answer.
If your backups are not that good your starters can still easily make 40-48 minutes. Only in games where you're up 20 in the 4th quarter your backups will get decent minutes (12-20 or so).
If your backups are close to your starters skill they can make some more minutes. But even with a distribution like a 150k C backed up by a 90k C I sometimes still had a 44vs4 minute distribution. My guards are closer together in skill so they are more likely to make about 40 minutes as a starter as opposed to my bigs who often make 44+ in close games.
So yeah, the simple answer is that it depends most of all on your backups skill.
If you want you can look at my games. The lineup is usually:
A F
B F
C G
D H
E I
(so 1 guard backing up 2 spots and usually the bigs still make more minutes. The SF is often in foul trouble so his backup gets more minutes).
Crunchy! If you eat fast enough