Which makes me wonder whether, at 200 scale, a Matty's Models J-prop might not be close enough to adapt/rework to what you need in 350. Compare your desired prop, at the new (accurate) size, to your J-prop and let us know how close they look. (A slightly oversized J-prop would be good, since it would need to be reshaped/refined down into the "Bananna-Blade" style that you'd need.)
Of course, the real solution is simply for Matt Stein Models to develop an accurate, 7-bladed "Bananna-Prop" in 1/350 scale, particularly for that kit. (Save you money and look better than PE, when finished.) But I'm really in the weeds now; catching up with all the new release projects I'm already working on.
If/when I can ever start that project (which would then go pretty fast), I will definitely let you know, though.