I'm thinking since all of our fabrics are right next to WHITE in our quilts, I don't want to take the risk of not washing. BUT - like you I am eager to go, so am actually doing a different center medallion, and am well on my way. Yesterday, I realized I wasn't liking my vase fabric, so I drew a new vase on my Stable Stuff, and glued my fabric around it, perfectly. THEN, realized I had not washed this particular piece of fabric. So, I took a piece of my vase fabric, sandwiched it with a piece of the white, soaked it in hot water, then let them air dry sandwiched on a paper towel. There was no transfer or bleeding of color. You could/should do this with a swatch of each of your fabrics if you do not plan to wash them. Don't worry about slow! There are a few of us!!!
In super cold Montana