I use the Mr. Surfacer method. I use a small flat brush which by design is stiffer than say a round brush. Keep some brush cleaner nearby as the brusch will get gunked up at times and need to be cleared.
I presume all of the other methods also work which are listed above, The spray on Terra Cotta is great for making the "uniform" factory applied non-slip coating used on modern vehicles.
Rounds Complete!!