I agree, put it all together and then , tweek and listen. Then decide where you stand. The PV 12 is a very fine preamp. I had a 1.5t and a 1.0t way back and both were solid amps. Definitely retube, if you do not listen to vinyl you can start with tubes V5 and V6, 12au7 type. If you have a 12L linestage only there will only be tubes in positions V5 and V6.
Good luck and enjoy
Good luck and enjoy