Thanks Alex and Marcus.
Absolutely ill be rain testing, was always the plan. Why would you mention this?, no faith?, doubting my vast building skills?
Today I fitted the adjustable wheels (for sliding doors, from bunnings). Was totally surprised how well that went, the dome rolls very smoothly with a finger push.
The quick-release hatch allows very easy step-in access. I was concerned given the small size of the dome that access/standing inside would be a problem. its not.