Laughingman, I assume you use a wetsuit most of the summer and snowkite most of the winter. When skiing, I like the harness to spin freely so that the pull is coming from my side. As far as I can see, the Engine harnesses would not benefit me when skiing then. When snowboarding, it's a different story and I want the harness to stay in place. With a snow suit on, is there any advantages to this harness over others? Same question with wetsuits. I only kite without a wetsuit for about a month. When doing the mold, would it not be best to have a wetsuit on? When wearing a wetsuit, do you still notice close to the same benefit with this harness compared with others or do you mostly notice it just when kiting without a wetsuit?
This harness will not spin. Allowing your harness to spin is in my opinion a bandaid for another problem which is a fixed hook, I use a sliding hook.
The mold should go on your bare skin, there is foam and neoprene between the hard shell and you, so the wetsuit will not cause any issues and you will still benefit from the custom mold. 6mm or less is not going to make that much difference as long as it is consistent. I'm not to sure about a drysuit though as there maybe bunching but that would be consistent with any harness.
The harness being a hard shell (carbon fiber) molded to your back provides way more support then a typical flexible harness, this allows Engine harnesses to be much smaller and in turn provides you with increased mobility.
Finally, you can make it look anyway you want... this is secondary to function but still, its your harness do it like you want to.
Does that clear things up?