I used to own a 45-watt Mesa/boogie Rocket-44. 1x12 speaker cab, handful of EL84's in the back. I rarely gigged with it above three, and the band I was playing with at the time was pretty damned loud.
If this is your first tube amp, i think you're going to be blown away at just how loud a low-wattage amp can be. Personally, I'm holding out for a good high-gain multi-channel 10-watt head, because i really doubt I'll ever need more than ten watts running hard, and if I ever do, I'll be mic'ing it.
Half the fun of a tube amp is running it hard- a low-wattage amp allows you to do this without scaring off your audience. I'm sure 35 will be moooore than ample.