misfit429, I have tried the liquid rubber twice, and it worked perfect on our hi-lo roof. what I also like about it, is that before the application, the metal roof had some uneven surface from age and movement, once I applied a thick layer of the liquid rubber, the surface is even and smooth with no low points, of course the thicker application does requires longer time to dry, but within a week it was totally cured and lost the tacky feel. you are right on the heavy duty drill to mix the liquid and the hardener. first time I applied it was the rear half of the trailer, and I was using paint brush to apply, a year later I discovered couple of pin holes on the front of the trailer where I didn't apply before, I made a mistake of waiting 15~20 min before I applied and I noticed the rubber was getting thicker in the bucket, there was no way I could apply with brush, so pouring it was the other option, and I used a long handle squeegee to spread the material. overall we are very happy with the results.