I use a Dakine waist harness and the hook slides laterally on it. To be honest I donít really feel any difference from an ordinary fixed hook, but that could just be me.
To keep the nose down on my board I use long harness lines touching each other on the boom. This allows me to have a narrow grip, keeping the rig vertical and leaning my weight way forward on the board keeping the nose down. I also have my boom quite high and find that allows me to plan early, lighter on my feet and again lean my weight forward and go up wind easily. Throwing in a few fast jump tacks prove useful.
Give your new harness a few sessions any change will feel awkward at first.
Not against your idea by the way as my mate has a similar setup and if it works for you then cool.