Well, even though you can use all kinds of static applicators, both homemade and commercially made, I've found that for small surfaces, such as bases or small dioramas, those are not really necessary or even practical!
I've personally never used one; whenever I use static grass on bases (and I use it very frequently), I add a drop of (PVA) glue on the base, in the shape and size I want the grass clump to be, pick up a large clump of the grass of choice between thumb and indexfinger (at least 4x the size of the intended clump), and press it down on the glue.
I then tap/knock off the excess grass, and gently(!) blow
over the glued down grass. The resulting vacuum over the grass will pull the individual blades up and make them stand up. And this simple process creates really nice and realistic clumps of grass.
Even if I want a base or field to be fully covered in grass, I use this method, because grass, anywhere but lawns, football fields and putting greens, exists of many, many clumps, and doing it like this will break the monotony and will yield more realistic results.
As for what type of grass I use; I tend to mix my own blends, as using just one type will result in too monotone a colour. I usually mix light brown/yellow with green (lighter for spring, darker or yellowish for summer and faded green for autumn) together, often as many as 3 or 4 different brands/types. It's also important to note that I also tend to use varying lengths in a mix, to once again prevent a too uniform look.
As for length; I usually mix about 2/3 of 2mm or 3mm grass and 1/3 4mm or 5mm tall grass.
I hope that helps...