I have found that, for me, three is always the charm. This is the third time around at painting the tub. This time around I also painted the toilet seat and all the associated hinge parts.
I used more of the acrylic urethane paint from PPG. Here is all the products I used. The most important item here is the measuring cup. Careful measuring is key to this paint system. You are creating a chemical reaction and it is that reaction that makes this paint so strong. The primer is K36 and it is mixed 5:1:1 with a K201 catalyst and PPG reducer. This stuff is easy to spray and when dry, sands up like butter.
The top coat is the MTK line. I do not recall the color number, but it is called "Deep Aluminum" This product is mixed 4:1:1 with a MH167 topcoat hardener and PPG reducer. The top coat is difficult for the "not so shinny rivet named me". It needs to go on super thin and super fine.
I put down three very thin coats about ten minutes apart. The last coat was a drop coat that was to orient the metallic flakes in the paint. No runs this time...