Yes it's imperative that as you roll in different 6SN7s, you also roll in a rectifier. It's the combination that is key, as one or other will make or break the resulting sound quality!
Another fantastic sounding combination in my Modwright Oppo 95: a pair of Sylvania shorty chrometop 6SN7Ws (black base, green lettering) with an RCA 5R4GY. This combo gives me an awesome soundstage, great mids, and good balance on both sides of the sonic spectrum. Sweet!