Pretty safe bet to say 1/28.
It's got the same tracks/body dimenstions as the Panzer III and other recent TCS StüG, so should be the slightly larger dimensions that look more correct with KC, TGM, and TCS figures. Since the first Panthers I've yet to have a TCS vehicle that didn't scale closer to 1/28.
I am liking te sculpts of te FJs more and more as I look at them. The proportions seem to be very good, not too chunky, and they look a lot "crisper" in detail than some of the recent figures. Same for the figure sets from the Sturmtiger. Looks to be a good direction TCS is heading in.