I'm not sure if it's of any benefit to you in any way but the timber sandwiched between 2 strips of aluminium may be a little restrictive, then again it may not and I may well be misunderstanding the design you've described, it happens with my brain or what's left of it..
In the past with a sliding timber surface I attached the tongue out of yellow tongue particle board flooring and it gave it a nice smooth surface for the panel sliding movement up and down. It was only a sliding shelf in a complex computer table I designed and built but with the plastic or whatever it is it made for a very nice sliding finish. Bunnings sell the tongue on it's own, worth keeping in mind.
It's a polypropylene strip:
https://www.bunnings.com.au/poly-eig...eeder_p4430566
Are you going full fibreglass shell over the dome?
I don't like playing with fibreglass but have canoes and have had no choice in the past, good luck with it.