Fabric adhesion to the tank is good as long as you follow the instructions as Dave summarized below. The only problem I had was a couple of spots on the top of the tank were dished in and I didn't notice it. When I shrunk to 350 and then applied the polybrush, those dished in spots wouldn't stick down. There are only two of them and they are not very big, so I left them as-is. In hindsight I should have leveled them out with Super Fill before covering.

It is not clear in Dave's summary, but don't glue (Polytak) the ribs to the fabric before shrinking, except the tip and root. I believe the manual says to put two coats of Polytak on the ribs and let it dry. Then cover and shrink. THEN reactivate the Polytak underneath with MEK diluted Polytak (I think. I am going by memory). This method allows the shrink process to equalize over the whole wing surface, rather that one bay at a time. On the bottom concave surface when you reactivate the Polytak you will have to press the fabric down and probably use some weights to hold it down while it dries. Later you rib stitch and it won't come loose.