"just a little cool in the midrange, just a little hot on the top end and images could be a little rounder"
I've never used the Amperex 7308s in a phono stage, but I do have experience with using them in a line stage. If that is transferable (I don't know) then you might try some Siemens E88CC or E188CC 'A' frames from the early 1970s. These are not too expensive and they are a little softer on top, have warmer mids and give 'rounder' images than the Amperexes. At least that has been my experience in a line stage. I personally like the 'pinched waist' D-getter Amperexes, but finding a phono grade pair would probably set you back and arm and a leg and probably your left nut too! You might cruise Ebay and keep a lookout for some D-getter PQs. Still rare, but not nearly as costly as the 'pinched waist' variety; similar sound. I recently bought a pair of D-getter E88CCs for $30. good luck.
I've never used the Amperex 7308s in a phono stage, but I do have experience with using them in a line stage. If that is transferable (I don't know) then you might try some Siemens E88CC or E188CC 'A' frames from the early 1970s. These are not too expensive and they are a little softer on top, have warmer mids and give 'rounder' images than the Amperexes. At least that has been my experience in a line stage. I personally like the 'pinched waist' D-getter Amperexes, but finding a phono grade pair would probably set you back and arm and a leg and probably your left nut too! You might cruise Ebay and keep a lookout for some D-getter PQs. Still rare, but not nearly as costly as the 'pinched waist' variety; similar sound. I recently bought a pair of D-getter E88CCs for $30. good luck.