I think that’s a great idea and luckily 15mm is small enough (and your table large enough!) that I think it’ll be possible. I like the idea of moving from landing in hueys, securing the area, building a base and the inevitable counter attacks patrols etc all on a static table. I know you’ve said you’re using Battlefronts rules but I can put in a vote for Ambush Valley (I think that’s the name of the Force on Force Vietnam ruleset). Looking forwards to seeing how you do.
BALM