I have to agree from what I've read regarding tube rolling that a set that are not within the manufacturers tolerances could be costly trouble. I thought this post partially explains ARC & replacement tubes especially the last couple of comments.
http://forum.audiogon.com/cgi-bin/fr.pl?aamps&1295643194&openfrom&1&4#1
That being said you want want to try the Gold Lion KT88 re-issues. Jim McShane does a great job of matching (and I'm pretty sure he knows ARC's specs). On the other hand if you want vintage tubes I really like the original Tung Sol 6550 solid black or grey plates. Very smooth highs - liquid mids with decent bass. Extremely musical tubes. Be aware those can be very expensive especially since you would need 4 matched pairs. I've also read the Shuguang Treasure KT88's have a punchy bass and a huge sound stage. I have no experience with them though.
Good Luck and happy holidays
http://forum.audiogon.com/cgi-bin/fr.pl?aamps&1295643194&openfrom&1&4#1
That being said you want want to try the Gold Lion KT88 re-issues. Jim McShane does a great job of matching (and I'm pretty sure he knows ARC's specs). On the other hand if you want vintage tubes I really like the original Tung Sol 6550 solid black or grey plates. Very smooth highs - liquid mids with decent bass. Extremely musical tubes. Be aware those can be very expensive especially since you would need 4 matched pairs. I've also read the Shuguang Treasure KT88's have a punchy bass and a huge sound stage. I have no experience with them though.
Good Luck and happy holidays