Rolling tubes in the Rhea is difficult without a tester. I tried for a few months without much luck and finally bought a VTV. Since then no problems.
V1 & V2 should be treated as a unit. You can't assume they are matched pairs because only the sum of the gain in V1 & V2 has to match across channels. Unless you know what's in your Rhea or you have access to a tester, you may have more luck by replacing all four tubes with matched pairs. With a tester you can save some money by matching pairs to pairs.
For example V1L may test at 100/90 and V2L may test at 90/100 giving you about 190/190 as the total for the left channel. These would match with two tubes that each test at 95/95 (or one at 97/97 and the other at 93/93) in V1R and V2R. Tubes from the factory will often measure this way so that's why you may have difficulty rolling just a pair.
V3 and V4 are usually matched pairs but sometimes a slight channel mismatch in V1/V2 can be corrected by putting in V3, tubes that display a mismatch in the other channel.
V5 are the easiest tubes to roll because they're only used for output and provide no gain. These tubes do not have to be matched, just quiet.
I prefer the Philips (including Heerlen, Mullard Blackburn and Valvo Hamburg) longplates for V1 & V2. They only made these tubes until 1959 so they're rare and expensive. If you can afford to put them in V3 even better but good shortplates will do in V3 and V4. Again I like the Philips 7308 in V5.
Telefunkens sound almost as sweet to me and I can understand why others may prefer them. As Telefunken never made shortplates (I may be mistaken), they are easier to find.
It may cost you $1500 or more you get a full set of QUIET, NON MICROPHONIC matched tubes from a dealer for all five stages in Philips and perhaps slightly less for Telefunken. These tubes will make your Rhea sing.
I do most of my tube buying on ebay now but you can find good deals right here on audiogon from time to time. Ebay's hit and miss but I think that I'm ahead as compared to buying from a dealer.