With regards to the SS x SNS collab:
I've read people say they fit like 1.0 and others say they run 1/2 size large. Personally, I don't trust what other say anymore without trying the pair on myself. Wide footers advice is bad for someone with narrow feet and vice versa. Others prefer a loose fit with extra toe room and others prefer a snug fit with minimal extra space.
Some people went TTS on the RC 1.0 and others like myself thought they felt loose even at 1/2 size down. I went 1 full size down.
As for the SS x SNS, I went 1 full size down like I did for the CNY 3.0 and NC 3.0. If the toebox is wider then normal and the knit even remotely loose, I think I should be good. If not, I'll get rid of it and get a US 11.5
Note: I don't get toe bulge on my UB that I went 1 full size down. My feet are narrow and not very large/thick height wise either.