would like to know what kind of plastic sheeting is better for masking door jams and trunk opening,
The heavy plastic is 3 mils thick and the light plastic sheeting is .0003 thick.
do you have a problem with tape sticking to is ?
what's the best to us

3 mil is pretty thick - sounds like some sort of builders plastic. We use the real automotive masking plastic, the stuff is very thin. Paint adheres to it, and it will not later have loose paint chips or flakes coming off it and getting into your paint. Make sure you get the real stuff not rolls of plastic from a hardware or department store.

I use this but I don't buy it from this site: http://www.nationaltoolwarehouse.com/12 ... ArWH8P8HAQ

Yea. Don't use the cheap plastic sheets from the hardware stores.
When you wrap them up and gather it to throw away. Paint starts chipping and it makes a big mess. And as Chris said, it will get onto your new paint.