Replying to custom twin-tips?

ok guys, i've heard a couple comments on this and asked a few questions, but tomorrow i'm actually gonna go for it and try to bend my old skis and make them into twin-tips. Yeah, this is kind of ghetto, but hey, i don't use 'em anyways so i might as well try it. So my question is: does anyone have any specific advice on how to do this (right now i'm planning on torching them and bending em in a vice), specifically whether or not i should heat just one or both sides, and if i should do it little by little or all at once. That kind of thing...