If you use a roof mop, and if you slop enough of the stuff into the cracks it will create a nice layer that will solve your needs.
I have used this stuff on metal home roof additions and the key is to keep the product constantly stirred up. The metal flakes or whatever seem to constantly sink to the bottom and you need this on the surface to work properly.
Have one sloping it on and another stiring from the bottom up.
Lay it on thick and it will self level. If you are concerned about certain cracks, then use a good Butly Rubber Caulk on those areas first, let dry and then coat it.
This product does not last forever and in Texas, the sun will eventually cause it to crack and open up. Then you re do it in those areas. This is only in areas with severe heat.
Also, remember it has a cummulative weight thing, the more you add the heavier the roof gets. So be careful.