I have used Charlie Price, Vintage Speed: http://vintagespeed.com/ he has supported my carbs on my avatar, he also has the thicker gaskets, as indicated in the photo. Some on this site have not spoken well of him but I've dealt with him often over the years and recommend him!
Daytona carburetor parts makes the best rebuild kits for vintage carburetors. http://www.daytonaparts.com/ Bill
I'm a big fan of Charlie at Vintage Speed as well. I myself have never had a problem with service and his kits are the best I've found. I prefer his "Master Kits" as they include your choice of jets and power valves/plugs for dumpers. I've also added his screw kits, (H-2-kit), or in SS to my rebuild orders. Nice guy to deal with to boot. I have an order going out this week for 14 more kits. I do quite a few multi carb setups here.