The Results

This is the 'before washout' shot, all wet and waiting.

I am very happy with the way the colors turned out, so pastel. Especially the yellows which are much sweeter and lighter than the garish wet version. As expected the reds went all pinky-watermelon and the purples leaned toward pink rather than blue. Speaking of blues, I already have loads of turquoise but not that cooler sky blue, robin's egg blue. Now I have some, but not enough. More blue dyeing in my future.
Those wimpy greens just about disappeared into yellow which is OK since I have loads of greens already. In fact, the amount of yellows in my stash, pre-dyeing, was minimal and now I feel closer to what I need for my palette. When yarn shopping next time, notice how few yellows are available.
My goal was dyeing for lighter colors, more summery and sherbety. Since I have so much wool which tend to be for winter garments, I felt a big gap in the value range. I may add some wools to this mix, and some silks, since there is also a big box of white wools in my closet too.
The difference in wool or acid dyeing is that a really great purple can be dyed, which never seems to come out right with cellulosics. When I see a great purple cotton yarn, I buy it right up.

To reply to some comments:
Mordant is not used with procion dyes, as it is fiber reactive and uses sodium cabonate at the fixer.
To get a true red, which I was not after, I could have used a bit more dye. But I was after a light warm pink and therefore I knew from experience that a teeny speck of Fire Red would give me the desired depth of shade. For the amount of yarn I was dyeing I used an unmeasureable amount of dye and continued to add specks of it until I saw the right results, knowing the wet yarn would wash out and dry much lighter.
It is not so much an unknowable result, but each yarn did take the dye differently and that was fun to see the differences in the washout.