Questions about rolling tubes that show my ignorance, please explain!

My Vincent 236mkII has three 12ax7 tubes, not much compared to "real tube" equipment. The main or window tube that seems like the V1 tube in a guitar, gives the unit its overall sound.
Then the signal splits to a left channel and a right chanel.
When I use my Amperex foilD getter 1956 in the General/V1 spot and the two Mullard 1956 long plate square getter in the left/right inputs , the sound is full and very tube like in a 1950s type of character. My Uncle was a Dynaco and Heathkit nut and his apartment was filled with amps from that era and the sound is familiar.
When I switch, and put the Mullard long plate 1956 in the main V1 spot and the two Amperex foil getter in the left/right inputs the sound is still very good but more Telefunken if I had to describe it, and I personally dont like it as much.
It seems where a tube goes is as important as what a tube is. This opens up a can of worms for tube equipment cause depending on how many tubes your unit exbounds it can be an extremely exhausting excersize.
Other than saying "experiment" what does a tube lover do with specific tubes in specific inputs.
Take care, Thanks in advance, John M.

 

I know it sounds like a confusing question but its not. Is where a preamp tube goes as important as what brand it is? John M.

 

This is to you Mr. Hoffman, You probably do not know the outlay of the Vincent but in your experience the window tube or Common tube seems to be very influential and then spliting the signal to left /right tubes furthur adds the timbre to that tubes sound. In this simple case I find the Common tube (my word) to be the most important musically and harmonically and what comes after augments what is fed to it from that tube. Oy vey! Thanks John M.