Strategy 400 Stereo tubes

[Eric B]

Need to know what I can keep in my Strategy 400 Stereo and what to replace. There is a mix and I don't know squat about tubes. The more I read the more confused I am about the options and what it will do. I obviously can't buy them all and listen with my own ears so I'm looking to the board for advice. What positions do what and where would matched pairs go? Is the arrangement mirror is 1 2 3 3 2 1 or 1 2 3 1 2 3.

It sounds good with my Studio Recto Pre but very dark. Interersting though.
Thanks.