Velcro stickers and rubber feet from the 1-Euro store, and the handle of an old toilet plunger.
I had to flatten the plunger handle on one side to make more of the velcro stickers connect.
With tenting I really would like to have more aggressive staggering for the pinky column though.
May I ask what caps those are?
I have the same ones, and I got them on Amazon: https://www.amazon.com/gp/aw/d/B098QZM2HP?psc=1&ref=ppx_pop_mob_b_asin_title