Tube pre- or amp: does it matter?


I'm considering introducing a tube component into my system (Cary 306/200, Placette pre, Macintosh 300, Gallo 3.1) to bring out a little more depth, staging and musicality. I'm willing to start from scratch with both the pre and amp. If I were to balance tube and ss, is there a rule of thumb about whether it's better to have a tube for pre or a tube for amp? All things being equal (which they seldom are) would one make a bigger difference in sound than the other? In my electronic ignorance, I'm wondering if there might be something about whether the tube is closer to your source or closer to your speakers. (Of course, I may end up with tube for both.)

Thanks for any help,
I also suggest starting with a tubed preamp. I think that the preamp exerts the greatest influence on sound quality. Also they're cheap and fun to tube roll. Enjoy checking out different preamps, I own and love my Herron and also recommend Joule Electra, Supratek, Air Tight, First Sound and many others. Have fun and happy listening!
Why not try a tube integrated and see how you like the sound. There are plenty of choices new from Cayin and Primaluna to Cary, CJ, ARC, or VAC on the pre-owned market. I started with a tube integrated in a second system which prompted a switch to tube separates in my main system. You didn't list your music preference, but from my experience tubes would only be a disadvantage for techno electronic or heavy metal type rock.
The Arc LS25 was a great match with my MC300, great tight bass and better extension on the highs than using a Mac solid state preamp. The Arc wasnt too tubey, had AU24's all around and was quite happy.
Another thought would be to also listen to the hibred amps.
I had a Moscode, which was tube input and S.S. output. 300W. Old circuits I assume as there was something about that unit that was lacking air. but alot of tube gear can seem that way. As well, S.S. can seem thin and shrill.
But there is a CJ that is tube in and mosfet out and that might also allow, (maybe) for a passive pre, which can add clarity that few powered pres can match.
If i had to do it, I'd get a VAC, or Joule pre, or an ARC and run it into S.S. That way you are amplifying music, even if thinning it out; as opposed to squashing music or squashing thin sound with tubes. I'm trying to figure which could be the worst outcome, and I think I'd go tube pre or tube hibred amp.
I have not looked at the other posts, so sorry if I'm repeating anything. Just focus on the amp/speaker combo and stop even thinking about the front end for now. The amp will-WILL make the biggest real (musical) difference of any component period. It is where the music will come alive or not. No other component can make the kind of impact that the amp can. A preamp is important when and only after you have the amp of your dreams. use a cheap pre with a statement amp and it will kill the statement pre/budget amp hands down. I wish the stupid mags and reviewers would just admit the amp is king and people would'nt have to keep trying to upgrade their way overpriced allready cd players and or go for even more obsene expensive speakers trying to get better sound.