Opportunity is missed by most people because it is dressed in overalls and looks like work. - Thomas Edison
I can't speak to the inks you're using specifically but I print on ribbed tanks several times a year using Union plastisol with no additives. Customer is happy each time.
Thanks guys, I appreciate the feedback.Colin, it is a 2/1 rib tank-top, the one with "courser" ribs and it is a pretty stretchy.I will start with about 10% and see where it goes.Any other pointers...anybody.... or that is all that is different with ribbed tank-tops.
Just buy a few extra. You are going to have a few F'ups. Watch your dot gain because you will have to get ink down in the valleys that are there from the ribs. Post up some pics when your done.