Ultrasonic bath for carbs

Hi all

Does anyone have any tips on using an ultrasonic bath for cleaning 912 carbs? Questions I have are as follows;

What type of bath? 

What size?

What type of solution? (are they still effective with water alone and if so does it have to be distilled water?)

How long should a carb body and internal parts be left in the bath for?

Does the solution need changing after each carb clean?

I have heard issues of the epoxy resin bonding being broken down inside certain carbs (the black bodied carbs in particular) following an ultrasonic dip resulting in the air passages being blocked. I have read of others mentioning that carbs can become discoloured if left in for too long. Has anyone else heard of these issues?

What may be the effect of immersing o-rings in cleaning solution that may still be housed inside the carb body? It seems the majority of people who strip down a carb for cleaning may indeed remove all internal parts and o-rings but do not remove the throttle shaft o-ring(s) due to having to remove the more challenging butterfly valve retaining screws. These o-rings inevitably end up getting dipped.

Any other gems of knowledge relating to ultrasonic baths?!

Cheers

Shelley