At most, taking a hero out of the CB costs 3,000 manuals. Retiring heroes that aren't needed can get those relatively easily. Not that that even matters, it's more of a last resort than anything. Dragon Scorch isn't exactly rare, so chances are the OP already has a rare one.

You call it a waste, I call it an investment. Dragon Svorch can hard carry a player all the way to Twine. That more than makes up for any cost imo, especially if the OP is having a lot of trouble right now.

At PL22, the OP doesn't need to worry about farming (at least not on the level that most of us think of). A farming build is totally unnecessary. Same goes for a B.A.S.E. build. Pre-Twine, those aren't really needed unless the OP plans to solo everything.