I promise you, we are direct feeding (to use your term...we just call it tucking) the material into that channel. No, I don't have a TON of experience doing wraps, but I've worked on my fair hare, and my install help has multiple years doing them. We absolutely, positively, aren't bridging the gap. In fact, that particular body line is extra difficult because it's so tight that we have to keep popping the vinyl OFF the body just above the body line while we're working it into the groove.
I did use the 3M primer on a previous E150 with Oracal vinyl and had horrible problems, eventually having Oracal tech support themselves tell me to NOT use the 3M primer, that it breaks down Oracal's adhesive, causing it to release from the vinyl surface itself. That's their story...I'm not saying it's right or wrong, just that's what they told me.
Now I'm not going to promise that the vinyl wasn't stuck to the top side of the V shape of the channel as we were working it onto the bottom side, but I really don't think so. We were very deliberate.
As for how much heat, the Oracal rep himself told me that you have to heat it almost to the point of melting. When we press the squeegee into the vinyl, it leaves a slight impression of the surface of the squeegee. So it's obviously warm. Any warmer and I would think it will burn the laminate.