It really depends on what cartridge your mounting and if your trying to add extra mass with the soundsmith's. I needed a few extra grams to get my resonate freq right so I used their brass screws and they did the trick.
Also since my cartridge also needed a nut on the bottom side, aka they dont screw right into the cart, those screws prevent you from having to have fumble around with a little screw driver while balancing the nut, which is nice.