If you are not running a good quality swivel in your harness presentations you WILL have line twist.Doesn't matter if you are casting them or trolling them.A harness is not like a crank.You have to use a swivel.
I do use ball bearing swivels.I get them from Jann's Netcraft.I get the size #1 with the split ring on both ends.Package of twelve for six bucks.I also buy Jann's duo-lock snaps sizes one,two and three.This way I can custom make my swivels on the water if I need to have a bigger or smaller swivel depending on whatever I am using.
Also make sure your weighting device is made so the weight does not spin. Use a bottom bouncer, keel weight etc. then use a good quality swivel. Don't risk a once in a lifetime fish on .05 cent tackle. Cross lock snaps are also important so you don't lose stuff like oh... let's say 30 jets. Right Larry? By the way I changed all those.
I use the cheaper swivels and have zero problems with them behind jet 40's. I'm using the ones that have the 3 for 1.29 at wally world. I've never had a line twist problem and many times I'm pulling six lines at a time.