I use a magnetic stirrer at volumes up to 400 - 500 ml max and at up to 300 RPMs in 10% gelatin. I use glass beakers, not SS due to the heat transfer problems with SS beakers.
Above these values, an overhead prop mixer is usable, but has one big drawback. If used alone, it does not mix properly at the bottom and the emulsion and gelatin can "burn" on the bottom. So, I use a combination of prop and magnetic bars above 500 ml to prevent "burning" on the bottom.