Good idea on splitting the .5" down to .25". I've recently split some .25" into 0.125" (minus kerf of the bandsaw blade) for heat bending/thermo forming. It is a little tricky to get a perfectly consistent thickness at times, but I'm just doing small pieces for "artsy stuff" experiments so it's not at all critical.
Corian bends easily when heated properly.
A 225 oven/heat box does a fine job and once you have some practice a heat gun will do it.
Wear gloves!