fleacr

I just purchased a Princeton Reverb reissue and wanted to try out different tubes in it. It calls for a 5ar4 rectifier but I wanted to try a 5r4wgb Bendix I have bought. So the first question is, can I swap those two without compromising my amp (do the pins match...). Next, it calls for 3 12AX7 in the preamp stage. I have bought two 5751 RCA 3mica blackplates and one 12AX7 NOS mullard. If by putting the 5751's first with the mullard in V3..well actually I guess the question is, can I mix and match like that as long as the 12ax7 is nearest to the power tubes? What I'm going for is a nice clean tone from the first two, and then having the mullard come in to both boost the clean as well as add come of the nice mullard warmth to the signal (in my mind, that will work but I dunno about in reality). Thank you very much!