Hello everyone ~ Thank-you from the bottom of my heart for all the advice and suggestions. The blue pen I used was not the disappearing type it was one that would disappear with water. Perhaps Thimblebugs comment that the pens may have been on the shelf or warehouse and was 'old' is why it disappeared without water.
DH has huge conference table at work and we marked it with the Frixion pen after testing the quilt fabric to make sure it will disappear with heat.
So now the journey of attaching the Yo Yo's to the quilt begins. I'm thinking Greensleeves comment about wondering what 7 thousand Yo Yo's look like I may take them out of the bags (200 per 1 gallon zip lock bag) and pile them up and take a picture.
Does anyone have a suggestion how to wrangle a king sized quilt on your lap while sewing on the Yo Yo's? I don't have a hand quilt frame...thinking I will just take portions of it onto my lap and let the rest drape into a box.
Again, thanks to everyone who took time to reply with thoughts and suggestions, I'm very grateful!