How/where to acquire Premier carbs

If I had a mind to order new Premier carbs for my 74 850 MKII, where would I buy them where I could specify exactly what I want? I've seen posts here that some come with 17 pilots instead of 19, and I know that ordering for an 850 Commando can get you 230 mains instead of 260's. If I order some I'd want them to be configured exactly for my bike. Slide cutaway, needle jet, main and pilots as I need, not a generic "this might work" package.

I got mine from RGM and they fitted at no extra cost the exact slides, settings & jets I required
They also checked no swaff was inside

I bought Premiers directly from Amal correctly configured for my bike. I have purchased from The Bonneville Shop on another occasion. Even with shipping from the UK it was cheaper than USA vendors selling the same thing. There was swarf inside, so plan on taking them apart and cleaning them
regardless of who you get them from. Amal will correctly stamp the code on the body whereas the ones purchased in USA will be generically
stamped "R300" or "L300". It did take about 3 weeks for delivery partly due to COVD-19 issues. You will love them!

ebay, just message the seller regarding the pilot jets

If they are generic bodies then remember to do the cuts to the flange for clearance and check the redundant inner throttle casting for clearance too as they can touch.

Wouldn't OldBrits config them to your spec? I think there's at least one forum member that lists these on his web site (Greg M.).

I would trust Old Britts the most, to get the right jetting, etc.

I would prefer that they be stamped with the correct numbers, and no way I'm gonna take a file or grinder to new carbs. I'll check the Amal link, thanks.