I have used flat latex exterior paint on many projects but I haven't used the SW brand, used the brand sold by Lowes. I have never used a clear over the latex because once it dries it is dead flat, very tough, can be wet sanded, is easy to repair, etc. In the photo below the grey colors are flat exterior latex. If you have any specific questions, I can try to answer them.

Nelson Hobbies and Warbird Colors sell a water based epoxy paint. I have not tried these paints yet.

Kirk