Hopefully 8 to 12 flanges/side. 6 at the very least. Or just 2, or make it just as a one handed warhammer.
Please, 4 flanges/side (3 or 5, too)／Lower than 6 is not feels like it’s good to/for “just swing anyway”: There’s might be an exception, but unlike the swords or an axes, it doesn’t has to be make your weapon’s edge stable as possible, because of it’s shapes; has a many side/flanges(edges) or ball/onion, disc like shapes.
And most importantly, it is/will looks better.