For me, (left handed), my tether goes around me on my left side. I don't keep much slack in it sitting but I wouldn't call it taut.
As far as shooting interference, there isn't any for me. I have a treestand in my yard that I practice from, and I've shot extensively both standing and seated. It's something you would have to try for yourself, you could tie a rope or strap to the front of your belt to simulate, from the ground of course.
I found the RC harness to be the best option for me, but like everything else, you have to use what you're comfortable with and confident in. There are some videos on youtube comparing falls with each style of harness.