Hi Brian;

The bubbles come about because of the viscosity of the varnish and our rubbing or brushing "enthusiasm." I get pretty enthusiastic and have to keep my varnish thinned a bit - Not a whole lot, enough to allow the bubbles to rise and escape depending on how vigorously I apply it. If you can work slowly, you won't have to thin and you'll get more build per coat. If you work quickly, you'll have to thin and require an extra coat or two.

As to build thickness, I went vigorous-thin/6 coats and it produced a thick build - My thinning after the first coat was 5-10%, no more. If you don't intend to sand/buff after application, fine sand (#400) the next-to-last coat and _slow down_ and thin 10% for your final coat . . . This means slow hand speed as you're applying . . . It should go down like glass. It takes practice (surprisingly) to slow down the wiping motion. We all tend to rush it.

Really hope this helps, Spidey