Well, Rod, I am impressed. Not only have you got a hangar where you are allowed to do maintenance, but also you are a competent mechanical engineer
and a competent electronics engineer
I know there is a strong correlation between [real or assumed] DIY skills/capability and homebuilt ownership (after all, you would not try to build your own plane unless you had the copious time and facilities) but somehow I think you are being over-generous on the avionics repair capability of the owners
FWIW I have seen plenty of these products at exhibitions, and some are no less complex than the certified ones. Your eggs are in one basket - regardless of whether that basket is ICAO certified. A significant portion of the separate v. integrated decision hangs on one's attitude to aircraft downtime.