silicone fluid + dot 3 0r 4 = very bad, sludgy gunk in your system.
why do you want to change it out? silicone has some nice advantages over standard fluid, namely nonhygroscopic (doesn't suck up water)
i made a pressure bleeder too, i'm trying to figure out how to make it work on my 52. it's the easiest way to bleed brakes i've seen.