Looks like a really sweet spot, like everyone else said, commit to harness lines. They don't look to far wrong position wise when your weights on them, from what was on your footage but you should be able to let go briefly and the rig stays put with just your weight supporting it.
It looks like you're at that hurtful stage of learning where you're hooking into the harness lines, but still learning to hook into the foot straps. When you're confident with finding the footstraps without looking, practice hooking the footstraps first (both front and rear), then the harness lines...it's far less risky than planing around hooked into the rig with the board bouncing around under you.
Stick with it, you'll get there