Which is better, gain in phono stage or pre amp?

Jyprez, in your situation with a SS phono section and a tube preamp, I'd say you are doing the right thing already.
The SS phono section is generally quieter than most tube phono sections when High Gain is selected, because there is no tube noise. You can use all the gain you want in the Plinius phono section. The Lamm preamp is tube, and tube input sections generally are very forgiving of any overload on the inputs. Also, the tube preamp may have some tube noise if you have to turn it up high.

So, your combination of high gain in the SS phono section and using less gain in the preamp, will likely give the least noise, and low probability of overloading the inputs of the preamp. Also, amplifying the very weak phono signals earlier in the chain typically gives less losses from lines, and connections, that can cause the very weak phono signals to lose low-level information before they get to the amplification stages.

I have found that the best set up to my ears was when I switched from a VTL Ultimate pre-amp and built my own dual mono line stage, with very expensive parts( kept to a minimum ) used 8 mallory high powered batteries to get enough gain to not lose detail, and combined that with a Vandenhull 2 High output cartridge. Whene you use batteries, that sense of electronic interference when your are listening into the soundstage dissapears. I'm supprised that complete battery powered systems never cought on in the high end audio arena. At one time, many years ago, I had my entire system powered by 24 batteries, and it sounded incredible. My VTL amps and vanderstein subwoffers were driven by ac. I had eight seperate lines run to my system. NO filtering, because no matter what system I used, I noticed and very small loss of information and a rounding off- a kind of pleasent softening of the music-but missing something,( as opposed to rolling off ) of the notes.
Ever try batteries?

later this summer DarTZeel will be introducing a battery powered preamp with a phono stage. i heard the prototype at CES in Janurary. it was amazing.....possibly the best i've yet heard. this was in a system using a pre fairly well known to me (and pretty damn good itself). the DarTZeel made the other pre sound BROKEN.

DarTZeel

i have been a passive preamp guy for the last 4 years and have yet to find an active pre that does it for me. the battery powered DarTZeel seemed to do all the great things my passive did but went even further with naturalness and dynamics.

at this point i see batteries in my future.

Textbook logic: use the step-up trannies in the Plinius rather than an active stage, for the extra db.

Unless, of course, you wish to change yr preamplification altogether as Mike suggests