The dealer at the show was named T. Campbell. Sorry but I don't have any contact info for him other than the fact he usually has a booth at the local shows.
Well, I'm not Scrivener, but I'll answer that. We've used Red Dot at the shop for loading pistol ammo for quite some time. It works very well, and would be an excellent choice. 700X is another excellent choice. Get your loading data from a Lee Manual.
There are cleaner powders out there, but Red Dot is not bad and is now cleaner than it used to be. Far superior to Unique, which the shop near me reloads with. We can always tell who's using those loads; it looks as if they're shooting black powder!
Red Dot is versatile, economical and readily available. If you are going to stock just one powder, it merits serious attention.
My vote is for 231 or unversal clays.univ has a burning rate vey close to unique
and burns cleaner but 231 has worked well in all my auto pistol cartridges and .45 Colt loads
The next powder I will be trying for 45 Auto is going to be Ramshot Zip.
I have seen and used the loads that Jim Conway makes with these, and shooting 100 of his lead reloads with Zip, leaves your gun cleaner than shooting 50 rounds of most factory ammo! That's saying a lot!