Hello,
Dome Parts from astroshop EU I found very good to get design ideas and dimensions from etc.
They have a few designs, come with a data sheet and instruction pdf's so you can get a fairly good check list of parts you might require as well.
"DOME PARTS GmbH is a company located near Augsburg, Germany, which specialises in the planning, development and construction of first-class astronomical observatories. "
https://www.astroshop.eu/observatori...ome-Parts-GmbH
https://www.astrogfk.com/