I’ve got the SS Nano’s and they are great. They have taken a beating and they still spin smoothly, tons of grip as well (grip is not about the no. of pins its where they are placed). They are seriously thin as well.
Decent platform size as well, which is one thing against the MG1’s, as I have had DMR v12’s in the past (which are the same shape I believe) and the edge of my foot would roll over the edge slightly and give me terrible foot cramp after a while.
I would be amazed if the pins are thinner on the WahWahs as they all seem to be a standard size, except for shimano MX30’s which due to shimano loving standards are smaller. Also bear in mind thinner pins bend easier, and if they are thru pins you have to snap them off or straighten them to get them back out of the pedal.
Straitline seem to have the best type, as they have a hex head on the pin, so even if you bend or snap the pins you can still get it out without wrecking the pedal.