Any ever used Amsoil in their RCGF engine?
 

It's safe enough, but it's dirty, building up on the sides of the piston pretty quickly.

Redline seems to be pretty popular, for just the opposite reason. It leaves the engine pretty clean.

Red Line, or Sthil Ultra

I ran amzoil for years in my engines . In the larger 100cc engines it wasn't that much of an issue but found the 50 cc and smaller engines ran hotter and built up a lot of carbon . I would not advise using it especially in the smaller engines under 50cc . The smaller bearings need more lube than 100:1 can provide . Even if you mix your fuel @ 50:1 using the amzoil will not provide the cooling via the oil that you need . The result will be hotter running and quick carbon build up and possibly premature bearing failure . I would stick with the Stihl or Redline at 30:1

The OP asked about Amsoil Dominator which very unlike Amsoil Sabre is a tolerably decent oil. Dominator has been around for years and is recommended for use at more normal mix ratios than Sabre. Dominator doesn't produce the hard, almost plated on carbon like Sabre does. If there were no other choices I could live with Dominator oil though in my opinion there are much more suitable oils to choose from. These days I'm a Red Line guy and after seeing the internals of several engines, I see no reason to look to any other oil choice.

And Dominator is what I commented about above.