The rendering of the antislip coating has been so far the most time-consuming part of this work. I used the technique described in this post.
First I applied preemptively a coat of primer on the surface, in order to enhance its "wetting":
Then I protected the zones without antislip using a liquid mask (in this case, Masking Sol Neo by Gunze). I found useless (and too much laborious) masking the bolts, instead I cleaned them later with a toothpick.
Meanwhile I added some details, like the tarpaulins made with lead foils and the cover for the .50 cal. machine gun solenoids, made with aluminium ones.
I applied, with a paintbrush, some vinylic glue diluted with water (the primer coating allowed an uniform wetting), then I spread with a small sieve some grinded volcanic ash. After that, I removed the masks and, with the tip of a toothpick, I cleaned the top of the bolts from the ash.
Finally, I applied another coat of primer, in order to fix everything.
This is an overview of the tank, assembled and with the primer applied. The running gear will remain masked until the base painting will be applied.