Joule electra Pre Amp -tube rolling

time to roll some tubes on my la 100 mk2. Quick review of some of the forums seems to convey that the joule is less sensitive to tube rolling and thus NOS may not be cost effective. Any thoughts from prior owners/experimenters would be appreciated. May be just a case to simply call joule an order up what ever they use. The line up i believe is:

1 - 5751
1 - 6350
2 - OA2
2 - 6EM7

Thanks all