I was just looking at the same thing - yeah, some parts have apparently gone out of stock and now have LONG lead times. Would love to hear people's experiences.
And this is the reason things like the Kensington MacSaver was developed:
https://applerescueofdenver.com/products-page/macintosh-to-powerpc/cables-amp-adapters-macintosh/external-cables-amp-adapters-macintosh/kensington-system-saver-mac/
Head over to https://tinkerdifferent.com/account/preferences and untick pretty much every mail notification.
Then maybe add back some - like for PMs and such.
Having followed your trials and tribulations on Discord, I can only say: Bravo, ol' chap! Well done!
The sort of tinkering I wish I had the space for.
Tell me more about your plans for an already quite insane PM9600?
The NewerTech is a cool addon, but could be one source of issues.
Did you try booting with the G3 removed?
There was a 110MHz model released late 1994.