the short answer about living with valve amps...

its exactly the same as a normal amp, except they have £30 lightbulbs on them.

and you have to turn them off when you're done.

Given your nice TT and cart, I'd look at alternative phono stages the sooner the better.

In fact, I think this will give you better sound per £ than the other upgrades you're looking at.

A second hand 834p (or another quality phono stage) will only be about £200 + the price of your existing phono stage second hand.

The improvement is out of all proportion to the budget IMO.... especially when compared to a wholesale pre/power amp swap.