Sell them both, restore your fwb sport for about £150 ( reblue £60, tune kit £90 tops, refinish stock yourself if needed )
Keep a lookout for a different hw85 in .177 if you still feel the need for one, that you could buy with the spare cash
I wouldnt mess with the barrel changes - because it would niggle at me and i'd wish i hadnt done it, even though they might be a great combination ?...
Does that last bit make sense or is it just my OCD taking prominence?