A few weeks ago I was right where you are at and started this thread:
It was super helpful to me, definitely give it a read as there are lots of great tips from the community in there.
I’m now feeling pretty comfortable using the harness all the time, from being in the water hooked in to getting on the board and getting up to jibing and sailing hooked in. It saves tons of energy, especially when you aren’t up yet so get used to just hooking in all the time. I am now finally making great upwind angles and starting to fold up the wing and surf. I’m super stoked, tons of progress these past few weeks and this thread and putting in the time learning how to use the harness were really the keys to unlocking all of it for me.
I followed the advice of the crowd and went with the PKS single point harness as recommended in the thread. I have all sizes and for me now with a bit more time on them I think the medium suits me best, so that’s my recommendation.