Here's a post on my gas de-doming setup: https://budgetlightforum.com/t/-/19641?page=1#comment-488717, post #160. I find 2 1/2 hours is about perfect. Usually I see bubbles forming under the dome by then. If you take the stars out, the domes are loose and I simply flick them off carefully with a tweezer - touching the side opposite the wires, flickng towards the wires - never damaged.