I used to have a '67 200S with cabinet, all original too. When the original old stock Tung-Sol 6550's died, I put in some JJ's and they sounded so good that I decided I liked them a lot. I sold that setup to get an SVT, but a couple years ago I got another 200S that I completely went through, and it had old stock GE 6550A's in it. I put some more JJ KT88's in it and it livened it up considereably. I've heard a Sunn 200S with pre-war EI KT90's and it sounded good, but the JJ's sounded better to my ears. I've heard good reports of the EH KT88, the Winged C/SED/Svetlana KT88 (not the New Sensor made Svetlana mind you), and the Winged C/SED/Svetlana 6550C. I've got the 6550C's in my SVT and they're great in there. All the tubes you mentioned are good quality, long-lasting, and good sounding tubes. If price is the most important thing, then get the cheaper ones. At Antique Electronics Supply,
http://www.tubesandmore.com/ , the JJ is cheaper than the Winged C KT88 by a couple dollars, and they're on sale right now.