I went through the same thing that you did the first time I tried.
My best purchase was the $15.00 touch up spray gun. First flash spray a coat of dura tec. Than lay on heavy coats to get the desired thickness.
I also use the spray gun to put the mold release on. It goes on easier and does not leave any streaking or gators
My Uncle always said "the right tool for the right job" Of course my wife thinks I have too many tools and not enough jobs....