Rabnani - I don't think you would be able to choose which tubes come with the unit other than EL34 6550 or KT88 for outputs. When I got the V70SE it came with SED EL34 or the SED 6550 or SED KT88. Since they are not made any more I would be only guessing what manufacturer Andreas can get today. I think the input 12ax7 is the Sovtek 12ax7lps and the drivers are Tung Sol 12at7 re-issues. At least that is what both my V70SE and V110 came with.
As far as trying different tubes it is best just to buy and try them for yourself. My personal favorite tubes haven't been made since 1959 (Tung Sol 6550 solid black plate for outputs). Now as you change input and drivers the sound of the outputs will change too and you just have to find the right combo that suits your personal preference. So far I have 10 different output tubes - 9 different drivers and 10 different inputs. That is an awful lot of combinations.
As far as trying different tubes it is best just to buy and try them for yourself. My personal favorite tubes haven't been made since 1959 (Tung Sol 6550 solid black plate for outputs). Now as you change input and drivers the sound of the outputs will change too and you just have to find the right combo that suits your personal preference. So far I have 10 different output tubes - 9 different drivers and 10 different inputs. That is an awful lot of combinations.