Hey Olde Painter!
Yeah things have changed--been a while huh? True 3o years ago metalic paints were,nt all so great
NOW you have plenty of choices--including those old Humbrol & Testors--still very much in use. As a matter of fact those Wargaming paints (Citadel are quite good,sorry), but you don't sound like a fan of any acylic (So may have missed the metalic paint revolution by Liquatex in th 80's?) Tamiya and Vallejo also make very effective metalics---If its oils you want you'll just have to give some different brands a try and see what you think---or else find some painting articles you admire and read what's in use--
Never met a paint that wasnt mixable-