I have tried the RFT...very gainy tube but way too smooth for my tastes...
Ei gives more sag to the tone whereas the tungsram is tighter and crispier...works great on my engl straight...
Tungsrams were my favorits for many years in marshalls as well...
Then I tried the pschycodave recipe
V1 - Ei longplate
V2 - Chinese 12AX7
V3 - Ei longplate
I still use the tungsrams in my Engl Straight though...I like them in there...
Its a nice aounding Marshall amp...
But no kerrang...no aggressive high mids...
More lay down smooth tones...
Very nice sounding amp but my jose modded 2204 killed it...
I had a thing with the original Custom...
It sounded good in every guitar no matter the scale, woods etc...
But it was a bit ice-picky in the strats and had an ear fatigue...
I found out that I didnt gile well with 43Rwg pockups...even the boutique ones...
I prefer the openess of the overwind 42...