45 years working on quality bikes and this is the very first time I have seen Sugino Super Maxy arms in a 50.4 BCD. The only other non-110 Super Maxys I've seen were ones with a fixed chainwheel (typically 52) - and even those often had holes for 110.

Having successfully used Super Maxys for almost all those 45 years, they get my nod. Their only shortcoming is not being able to accommodate a 74 or 58 BCD inner ring.