Aesthetix IO Signature Tube questions?

Hello,

I am very happy with my IO Signature. I am preparing to stock up on replacement tubes, hoever I am a little confused. The IO user manual describes that V1 and V2 are 12AX7LP; when I look for tubes do I need to get exact replacements? What does the LP mean at the end of 12AX7LP. Another thing that has me confused is that V3 and V4 are labeled in the manual, 12AX7WB, but the actual tubes that came with the unit are not both 12AX7WB, V4 is a Sovtek 12AX7WB and V3 is a Teslovak E83CCS. Is E83CCS a replacement for the 12AX7WB? The IO sounds fine with the tubes in place. What exactly is a 12AX7WB? Can I use any form of 12AX7 tubes for the 1st and 2nd input stages?

One final question; I see people rolling the power supply tubes by switching from the EL34's to KT-66s, is this a good alternative replacement for the IO power supply? I am new to the whole tube world and have had tube equipment for about 3 years, Octave 130watt mono amps and preamp from Germany. I use EHKT88's in the monos, previously they were TAD KT88's which were prone to giving up the ghost, probably because of my extended and high level listening sessions:).

I would appreciate any comments or suggestions about the tube questions. The IO is new and I am giving the stock SOVTEK's time to burn in.

One final note, I placed the PS under the phono-amp section yesterday (Copulare) equipment rack. The background became even more quieter, with a slight lowering of the tube noise floor. I am using 62db gain right now and at 9-10 o'clock positions on the preamp the music is plenty loud enough with deep room moving bass and dynamic enough to give you that breathtaking explosive feeling and transposrt you into the recording session, as if you are live with the musicians.

Thanks in advance,
Audioquest4life