I have used only one VDEPOT object with FinRus "Backwoods Airfields" runaways, because our fields were very small on those Continuation War days. You can use couple of them when making bigger grass fields like in the asw's great France map.
I have skinned the VDEPOD looking like sand and then I made gray colored VDEPOT_a filter: the blackest areas makes the VDEPOT object "invisible", so you can see the texture under it. When the filter's colour is gray, you can see about 50% VDEPOT and 50% texture under it.
Here's the FinRus' VDEPOT object:
And here's the FinRus' VDEPOT_a filter:
Asw has used them in France map totally "invisible" under all those nice grass fields (I think there are four of them). It's easy: just colour that VDEPOT_a filter totally black!
Then you can see only the terrain texture, which is normally "Grass" under airfields, because it's not bumby!;)
And of course, remember adjust VDEPOT object as "Runaway" and "Can not collide".
Actually I have used those invisible VDEPOTs under all Okinawa map's airfields, too, even if they have those (special) runaways. My opinion is that landing must be "Succesfully" on all areas of whole airfield, not only on the runaways!
And those special runaways in Okinawa map... quess how I made them!