I think maybe if you start your Backup SG then he will get 20+ minutes but your starting SG will also play a decent amount of minutes due to the fact that he has better skills than your Backup SG. I would play your Backup SG at the starting position. And then your starting SG at the backup and reserve positions and you should get a decent outcome as to what you want. You may want to wait for more opinions though.
Murray/Harris/MPJ/Grant/Jokic - 2020 NBA Champs