LPU people - Help!!

I have two coats of system 3 water based LPU on my Kayak now. I brushed it on with a foam brush. I started early this morning with temps in the high 50s and 70% humidity. When I finished the last coat it was around 71 degrees 50% humidity. I thined it with 25% water. I see a lot of streaks and splotches and brush marks and it just does not look good when the light hits it right. I would like to know what I am doing wrong and how to fix it. I am planning 2 more coats at least. Do I need to wetsand to take out the streaks or will they disappear under more coats?