I mostly used the “Holy Grail” Reflektor 6N23P (1975 silver shields). I also had a Dario Miniwatt 188CC (1962 or 1963, I think, one of the last years before they switched them all to Philips branding - not that it makes a difference, still manufactured by Philips in Harleen, Holland).
Once the Holy Grail Reflektor went in, it didn’t really come out. Just make sure you find an authentic one if you go that route- lots of fake Reflektors out there. Get to know the guts of the tube. They can’t fake that part.
"Holy Grail" Reflektor... I will have to look for one of these. Something tells me its not gonna be cheap