SL/PE9, which is more difficult: headstand or stall bars?

I have access to stall bars but I was wondering if it was more challenging to do this move in a headstand.

I've been already doing this move in yoga in the headstand position but freestanding (not my back against a wall), is it a good option to do it that way?

If done in headstand position you need to compensate the bottom position by moving the butt in the opposite direction of the legs , the butt will return in the normal position of a headstand as the legs move closer to vertical position.

Stallbar version does not have the balance problem.

I try to keep my hips (butt) over the shoulders and not move them at all when the legs go up and down. If I do it against the wall my lower back stays in contact with the wall, is it the right position?

I find stall bars a lot more challenging. For starters, when I am positioned on them I can drop my feet a lot lower than a headstand. In a headstand, the floor gets in the way... on the bars my head is about a foot off the ground, which gives room for my feet to pass the same plane as my head.

I find it a lot hard on the grip and wrists as well. The long sets add up...