Rogue MS-120 Magnum Monoblocks - tube matching

I have been lucky enough to score a pair of these monsters. I have some 12AU7 tubes I collected from a prior preamp I had, but they are 2 matching sets rather than a quad - a pair of RCAs and a pair of Sylvanias. Can I, and how would I, implement these in the monoblocks - i.e. I understand why you would want tubes matching in the right and left channels, but do the tubes need to match each other when two are used in the same monoblock. So could I, for example, put in one Sylvania and one RCA om each monoblock?