Thinking about it, the map should be really small.
16x8 is too big imo, after the walls disappear the teams should be right in each others face: As soon as its "go" units rush and in *A mods bases would be in artillery range of each other.
So 10 minutes building and then it all goes to hell in another 10 minutes

I think otherwise it just be ultra porc like a noob game on greenfield etc. Just think how much stuff you can build in 10 minutes if you do not need to worry about being raided, on 16x8 it would never end.
Darkside is 6x4, I was thinking in those dimensions.
Of course that is not much place to work with: so maybe just some concrete at the ends to give the idea of start areas and some other terrain in middle.

or even smaller:
The teal planes are the walls:

There will be features/units to block ground units without the small jittering.
The Lua wall is basically for aircraft only, which can not be stopped by features.
Also all units would be blocked from shooting until the timer is up.
And maybe also block vision of the enemy base? So you do not see what they are building until the last moment. Or always full vision might be fun too.
does it block humpjets-bots?
good question. Battle of the Luas? But even if it does not block them in flight they will teleport back behind the wall.