Snapped. Put it on and fold the strap over to see where it would hold best. Then take it off and snap them in. The back is still flexible enough to let you slide in after the strap is all snapped up
Mine are expected to arrive Monday. The TF size 9 fit well, but the Midnight size 9 felt big, so I sized down to size 8 on the Black SE. I hope I made the right decision...
I have the Tech Fleece in Black and the regular Sock Dart in Mid Blue. I find that the regular SD material is too thin and stretches too easily. Makes me think I could go down a size. Where the Tech Fleece version more snug. I'm guessing this is because the material is thicker.
I also were no show socks with all my sneakers. I've found that the Stance Super Invisible socks hold onto the ankle well (thin rubber grips) and don't fall down