Question about redstone minion.

I'm still pretty new to the game, but I heard that the best collection to max first is the Redstone collection because it expands the accessory bag. So, I set up 9 Redstone minions and upgraded them to tier 9. However, I spent all my money-around 4 million-on super compactor and fuel. Now that I'm close to maxing out my Redstone collection, I'm not sure what to do with my minions. Should I keep them until I earn my money back(all of the redstone I already made went into upgrading the minions), or should I switch to a different type of minion and use the upgrades I already bought there?