mc275 tube options

hello all,
I am currently auditioning a mac mc275 as one of my trusty dennis had triode monoblocks died the other day. I plan on getting them repaired and back in business, but I have always wanted a mac mc275. I thought after all of the accolades for this amp that I would really like it. well, I kinda don't. I am listening with an emotive audio sira preamp and janszen za2.1 speakers. my source is a cary cd308 upsampling cdp.

I am using the dealers floor model so it should be broken in at this point. I have a decreased soundstage compared to my triode monoblocks. imaging is also a little less than my current amps. however, the biggest issue I have and what is keeping me from buying this amp right now is that it sounds bright in comparison. the extra supposed detail and all that brighter sounding amps present is not necessarily a bad thing. but, in this case I have a john tesh track that has a triangle in it. with my triodes the location and detail of the triangle is very distinct. with the mac the triangle is muted and vague in it's location. that just seems weird. there is also a colin hay track, "don't wait up" that has shimmering cymbal hit late in the track. with my triodes the shimmer and decay is natural and very liquid sounding. it is muted and somewhat lifeless with the mc275. a tipped up more detail oriented amp should also have increased resolution, no?

I have read a lot about this amp needing the stock tubes changed. what tube will soften the edge without killing the detail? I can't seem to find any reference to sound changes by retubing the mc275.

I really want to love this amp. it is beautiful and I have lusted after it for a long time. I am hating this quandary I am in today.