I think the following standoffs work to secure an A3440 or A3660 accelerator in an A4000 Desktop:
Using a re-Amiga PCB and a Rev 1.1 A3660 accelerator.
From McMaster Carr. I have no affiliation, just a happy customer for decades.
https://www.mcmaster.com/catalog/131/3746/1836N73I did not test to see if they work in an A3000 Desktop, or any tower variety. I also didn't test any other accelerator, e.g.: BFG9060, but I suspect they will work with others.
The ones I purchased are the 18mm long, a 4mm hole, 1.6mm PCB thickness P/N 1836N73. When I purchased them, they cost $3.70 USD plus shipping for a bag of 10.
I did several trial fits and the 18 seem to work best. The connector appears to be fully seated and the PCB is very snug. I don't think they should be any taller.
Disclaimer, test them first to make sure they work for you, too.
Just wanted to give something back to a community that has helped me a lot.
David
