Thank you, PJW581. I have been there before but not lately.You would do well to study all DocRide's postings in the reference section.
They will help you make a well-informed choice.
You will also know where to look once you have your bag and want the best advice on general care and weatherproofing.
p.s. Traditional Barenia is the obvious choice that comes to mind, but you might need to search the pre-loved route.
(not Barenia Faubourg as that has not yet built up a long-term reputation, nor is it smooth)
From the leathers currently under production, I’m really liking the look of Evercalf. If Black Barenia was that easy to find (not even sure if they made it B 25s or 30s), could be would be worth pursuing, as it’s a gorgeous leather.
Fauve Barenia is another on my wish list, but Barenia Faubourg is not really...