As well as
@Blademonkey questions, to help guide a recommendation;
what brush or brushes do you use currently & how do like them?
Do you have a preference for face or bowl lathering?
Use creams, hard soaps or both?
I've recently bought a semogue 830 boar, it's the best all round brush I own.
It really does everything very well indeed and is incredible value.
For something a bit special Shavemac or Cadman badger brushes are truly top tier.
I would go for at least a 24mm knot (to feel luxury, a step up from the norm), 26mm is very nice, I wouldn't go beyond that. A good rule of thumb is a loft of twice the knot diameter as a minimum (that will be quite scrubby) & go up from there depending on what you prefer.
I've read very good things about the new stirling soaps badger brush.
I love spending other people's money!
If you're thinking about a custom badger brush there was a good explanation of the hair types & grades on "the golden nib" website (TGN). TGN sell knots that are well regarded.
For the razor, birth year vintage.