This. ^^^To have Mr. Hoyt open up a bore to 58 caliber will cost about $150 plus what it costs for you to get it to him. Currently have a couple one inch TC barrels (one each flint and percussion) he rebored to 58 caliber with 1-60 radius rifling. They are two of my best shooters.
But at $850, agree with @Artificer, the asking price is more than a bit high for a Renegade, even with a Hoyt rebore, although I haven’t purchased one lately, and prices are going crazy…. Suggest you look around more. Maybe place a wanted ad in the forum classified.
The going rate on Gunbroker for a 50/54 cal. Renegade in very good condition is +/- $400. Add in a rebore by Mr Hoyt and you are quite a bit under $850.