How much "shake" at idle is acceptable?

I’m not familiar with your EFI set up, but as general rule if you are lean at a cold idle it will backfire and pop and bang. If it’s rich it will shake like a dog shitting softballs.

I’m not saying you are rich at cold start, but I would suppose that it’s easy to get into the fuel table and have a look.

It could slow in timing too.