I’m getting tempted to try Team Yankee in 1/285 6mm.
I say do it, and keep the board size the same so that everything has more room to run around in than their 15mm equivalents, so you really get the benefits of dropping down in the size of the miniatures.
My 6mm Sci Fi project is slowly convincing me that I will switch over to 6mm WW2 as well. I think I can quickly paint up two armies and throw together some 6mm hedges and buildings. Or I could buy some 6mm resin buildings and paint them up, which is more likely. I have no problem doing that, apart from the money aspect.