if your plan is to use these grassmates, cut the footprint out bevore painting into the hole you cut, or the technic color will fall off after a while.
when you want to glue standart grass"flock" onto - forget it, you cant paint on that, specially not with technical color because its set up to dry out to give the effekt. but dry cracking paint doesnt hold onto grass.
tip 2: after your done with the base, and your mini is done - take a stroll to the nearest supermarket and buy the cheapest haarspray you can get (no name marks, the cheap stuff is more than enough) - but read before buy. hairspray or hairlack, but without shiny effekt. the cheap ones basically dont have them.
go home and spray your whole mini. it protects & seals everything from the paint to the sand and / or grass. so your miniature is conserved in a thin layer of hairspray.
human hands sweat, this sweat can (after a while) "grip off" the paint of your mini.
hope this helps
"We fight & we die in the name of the Emperor. This is how its always have been - and ever will be!
We are the Death Korps of Krieg & we will hold the line!!"