I went through the whole Garrard 301 Build last year and have not regretted it at all. I went from a oracle Delphi mk 4 and the Garrard has much more PRAT and musicality. worth every penny. I did the 301 with a custom bamboo plinth and Jelco 750l 12" tone arm. its a great combo and imo better then the vintage SME's a lot of people use not to mention less money. The new Jelco arms are even better. pictures on my profile if you want a peek. there is so many carts out there that is a topic many will give you suggestions just remember you will need to match the cart and arm together for compliance. other then that it was not a hard or nor frustrating experience well worth the time and cost ( total my turntable system cost me about $4k and time of course).
Tube pre's from the 50's I'm not too sure, I would consider looking to the 70's as you will find more available with some of the better names available by then.
I'm not that up to speed on the SS vintage stuff other then some of the stuff from the 70's - 80's
I've owned ProAc speakers ( response 2.5) and they are very musical and have good base for their size. they also image very well.