I've done some tube rolling but with an Octave integrated. First - I can't think of any output tubes at $50-60 a pair. Most current production output tubes are closer to 50-60 each. That being said you may want to try some Genalex KT77's. My personal favorite is the original Tung Sol 6550 black plate. They carry the EL34 sound but with more bass and power. Unfortunately production was stopped in early 1960. That being any original Tung Sol (made in the USA) tube carries that characteristic to a point. But all are very expensive. Finding 12 would be difficult. But back to reality. The current KT77's are closer to 150-200 a quad.
Not being familiar with the Cary if your amp is auto biasing you would need matched tubes. Otherwise if it is a manual bias you can get away with unmatched tubes but be forewarned if you get one with a low output and you push it with higher output tubes it will be the first to go (simple version). It's always best in my opinion to buy from someone who matches tubes because factory matching is all over the place. Jim McShane is one of the best for what he carries.
Good luck
BTW Tung Sol 6550 solid black or grey plates that test as new typically cost 300-500 each when you can find them.
Not being familiar with the Cary if your amp is auto biasing you would need matched tubes. Otherwise if it is a manual bias you can get away with unmatched tubes but be forewarned if you get one with a low output and you push it with higher output tubes it will be the first to go (simple version). It's always best in my opinion to buy from someone who matches tubes because factory matching is all over the place. Jim McShane is one of the best for what he carries.
Good luck
BTW Tung Sol 6550 solid black or grey plates that test as new typically cost 300-500 each when you can find them.