I do things only a little differently.
I use very cheap water dilutable PVA glue to cover the entire base.
Add the biggest rocks and logs or treetrunks, followed by sand and I let everything dry thoroughly.
When the base has dried I cover the sand and rocks with watered down PVA and let it dry again (add another layer of protection to make it virtually indestructible).
I prime the base black with a brush.
Paint the base in a dark brown, wash with black.
Drybrush with a lighter brown and drybrush again with an even lighter brown.
Then I paint the wood in approriate colors and do the same with the rocks (I use four shades of grey).
After the paint has dried I add PVA glue to the places where I want grass, add the grass, hold the model upside down and tap the base so the grass stands up.
Add some more spots of PVA glue where I want tufts or other vegetation, add everything and let the PVA dry.
You'll get something like this...sometimes I add tufts, logs or water:

As for what static grass to use, just buy the color you like the most or that fits best with you scenery or model...I guess any brand will do.