RE: What is the pupose of ESc capacitors?
You'd have to re-orient the ESC then, shorten the leads, don't know if it's really worth it. For what it costs the sphere is / had better be a well-designed ESC so maybe it has enough capacitance built-in. But the general recommendation in app notes and things like that is 5mm, half a centimeter or less for trace lengths, if it's longer than that it's probably not doing much good at all. And it adds weight / raises the CG, a little bit.