1. for degreasing sockets, use dishsoap. I pre-clean dirty stuff in the parts washer and let them drip dry (until patience wears out) and then into the uSonic. Once done, they get dunked in the parts washer for a final "oiling" cycle and then wiped dry.
2. for carbs, use naptha. don't use "real" carb cleaner, e.g. berryman's dunk. My experience is with chainsaw carbs - there's plastic in them and they don't work well afterwards (don't ask me how i know). Stihl doesn't even recommend carb cleaner on the carbs (mostly Walbro) anymore. If I purple powered a carb, I'd buzz them in IPA for a cycle or few and call them done.
3. if you have a small part and don't want to fill the whole tank, you can use the glass jar trick. It only works with glass. put the part and solvent in the glass and put it in the tank. fill the tank with plain water and let 'er rip. The water transfers the energy and the glass conducts it into the container. Not 100% effective in the jar but almost.
4. My main complaint about the HF uSonic is the plastic. If I'm doing a bunch of stuff, I'll get some tinfoil and make a lid and stick it in between the tank and the hinged lid to a> stop evap and b> keep the hinged lid's plastic/rubber from deforming.