It's an IG-88 head, by the way, molded from my Derwent engine burner can.
oooh
WANT!
when i'm using the smoothcast roto for a clone helmet, i do between 8 and 12 oz mixed per coat, and usually do 5 coats. this gives me a relatively thin, light helmet that's still solid.
the roto is slightly flexible, so it has good impact resistance. i've dropped a boba fett helmet from table height onto concrete with no damage.
a couple of other things i've found useful: have a bunch of throwaway brushes handy (i usually use 1"). that helps you get the stuff up into odd spaces.
i usually do one thin coat over everything, then a few thicker ones where i brush it around.
once the roto starts to thicken up to honey like consistency i start brushing it around until it doesn't want to brush anymore.
also, when making the molds, i try to leave a lip of silicone around the edge of the top to catch anything that might otherwise drip out.
the last tip i have is that i have a "slush blanket" - i big piece of cheap cotton duck that i throw over myself to catch drips and keep them off of me.
oh, and don't get the resin in facial hair.