Definitely been interesting watching you create this diorama base Mike.
Yes lack of space can be most frustating, but you seem to have found an answer that fits your problems.
I've wondered myself about doing some stackable dioramas, but with higher accessories such as your fence, makes, removable parts perhaps more useful, but then you lose the seamless appeal of yours.
Static grass using an applicator does help the budget a bit, since no one I think wants to spend much on the setting when the figures are the main attraction.
For myself I prefer using the longer static grass as more helpful in hiding faults. Another option available to anyone not fancying doing that, is to get sheets of static grass from Model Railway stockists . I have in the past got sheets approx 400 x 300 x 12 mm in a bright Spring Green and a late Summer yellow which you could cut to size.
Anyway, a well presented base does make all the difference in my opinion and you certainly have shared images of some excellent ones Mike and look forward to seeing you finish it.
On a side note, it was a shame TG decided not to widen their Royal Americans 60th Foot range in their FIW range of a few years back.