I'm running a load now - measured and it is about 1/8 cup.
My top loader as a low agitation (hand wash) setting and I use that - I took a picture but can't get it to load right now.
It didn't look like much more suds than what I normally get, a light covering of the surface but nothing significant.
I never gave it a thought that it might suds up too much before I started using it - silly me