I have a similar setup to what your describing. I bought a used Lyman GPR in 54 with the 1 in 60 twist. I got it off of gunbroker.com or auctionarms.com, can't remember which right now, for $175 + shipping. I got my 57GPR peep off of Ebay for around $30 and then bought a GPH barrel in 50 with the 1 in 32 twist from Midsouth for $127 plus ordered a 17 front sight for $23 and a 37 bead sight for the 54 barrel for $7 at the same time. The GPH barrel shoots 460 No Excuses very well and looks like it will be a good long range traditional shooter with the sight set up I have on it.

I'm not sure what model CVA you have but you might contact Deer Creek and ask them to check into their stock and see if they can find a faster twist barrel for you. I know that there were mountain stalkers that had a 1 in 38 twist, not sure if they had anything faster. When I bought my son's 54 bobcat it came with a 1 in 38 twist barrel that was very rusty inside, they sent a replacement that was 1 in 48 and pristine.

I hope that gives you some ideas.