I eventually came to the same conclusion and put mine in my attic. i wish I'd done it years ago!!!
I fought with different valve extentions that leaked or that didn't play nicely with my pressure sensors.
I tried to modify them with larger openings so that I could get at the sensors. It helped some but sadly I don't have the proper tooling so I butchered them a bit and they still weren't totally accessible.
Nothing but headache and grief.
By the time I pulled mine off, the wheels were thoroughly scratched up from all the times through the years I had to remove the simulators so I had to paint them. Since i did it mounted and with tires in place they didn't end up that great, but good enough I think.
No extensions at all, just standard valves. i can reach through to get at my dust caps in storage or to put my pressure sensors on when ready to go. It has been such a relief!
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