Tube preamplifier tube choice help please

I would like to ask which tube is better linearity and sound among 6SN7 and 6NP1 tubes in preamplification or what are their pros and cons
There are two brands tube preamplifiers I intend to buy they have almost same topology, one uses only a pair 6SN7(Tungsol) and the other one uses only a pair 6NP1 (Russian) they both have
tube rectifiers and roughly same prices
I have not used those tubes in any application before so I would like to hear your comments please.
Thanks in advance
there are at least a few vintage tube dealers on the net with extensive documentation on their sites regarding the different versions of tubes - especially 6SN7s.
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A lot of audio equipment manufacturers utilize the 6SN7 and millions of these tubes were manufactured for the military, so there is a good supply and more choices for tube rolling. My favorite 6SN7s are Slyvania for accuracy
For tubey sound I like RCA and Tungsol for smoothness
Agon Member JSAUTTER is a very knowledgeable source for tubes
Brent Jesse is a good dealer on the web. I have no comment or opinion on the 6np1