Dartwins are great crampons. You can stop worring
"I suppose what I'm asking is does the difference between horizontal and vertical make a big difference on ice, I suppose if the ice gets a bit slushy thebn horizontals are better, but iof it's slushy I'll probably not be stressing as much as I would trying to bash horizontals into bullet hard ice?"
On slush or wet ice the Horizontals offer marginally more support. On bullet proof, or really cold winter ice, sharp Verts are marginally better. But both are the extremes. Horizonals or Verts really doesn't make any differenece the majority of time.
Dartwin is a lwt and excellent all around crampon. Add a the Petzl bot for the heel and you are set.