no - I just squirt it in, but I don't measure the regular soap either. I like to go light on soap, I bet I add about 1/8th of a cup.

I've not had problems with die setting on fabric I'm prewashing that I use Dawn and color catchers. however I have had some bleeding when washing quilts after the are finished, and then I use regular soap and color catchers. Maybe I should switch to washing completed quilts with Dawn instead of regular detergent. So far it was one specific red that did this on two scrappy quilts.

Dawn is great stuff. i have long used it on my small farm to wash animal equipment, and last summer our vet recommended it to clean out an abscess in our pony's ear.
I also use it with vinegar to keep the shower clean. Starting with a clean shower, I spray the shower, walls and tub, an hour or two before I shower, then squeegee the walls when I'm done (I wipe the corners and chrome with a clean cloth). I have never had to do any additional cleaning and it all looks brand new. It is soooooo worth the few minutes it takes. I mix about 10/1 vinegar to Dawn.

I started the when the shower was new, if you've used an abrasive to clean yours, and the surface is compromised, it might now look as nice.

Dawn is similar to Synthrapol in suds production. At the laundromat, using a 6x front loader, I use probably 3 tablespoons. You could use more in a top loader if you are able to hand agitate. If you can’t control agitation, use less in the top loader. Using less also helps the rinse cycle get all the soap out of the quilt. If you use too much, you may need extra rinse cycles.

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 :)