We use very diluted Dr. B's in a foamy pump and it works great. I never measure exactley, I just fill up the dispenser almost to the top w/ water, add a big squeeze of Dr. B's (maybe 2 Tbsp.?), add a few drops of GSE and the end result is super foamy soap. The kids love it and so do I.
You have to have an actual foaming pump. Someone gave a link to a WAHM that sells them a few days ago, I can't think of who it was at the moment, though. If I remember, I'll add the link.
Found it
http://www.kindheartedwomen.com/bottles.php