@jl35 " it’s simply personal preference…"
Exactly. When I was exploring XP10/XP12, and XP20/XP22, I asked Nelson about running my Cary SLP-98 tube preamp or the SLP-05 paired up with one of the .5 or .8 Pass series amps - he shared in reply "we have many customers using your same tube preamp with our amps". So the preference comment is spot on imo, and while experiences seem to vary greatly with us all.
@hilde45 If I were in your shoes, I’d pick up a spare Linlai 6SN7 for your custom tube preamp, pair it with your Pass SS or QS tube amps, and call it a day.
i.e. Nelson likes tubes too in a preamp, another preference, with his own flat-tube version right here in a DIY preamp kit, supplied by Nelson: Korg Nutube dual triode kit. Well under your 1k state budget, at $299 for the kit. Several have tried it and like it pretty well. I’d put it up against many preamps already mentioned here.