Has anyone here had to do this in anger on a free hanging 10mm rope (on prussics) over a longish distance (say 30+ metres), how much harder is this than ascending a static rope. I imagine the risk of the rope cutting through is higher as its sawing more.
I've practised ascending short sections of free hanging dynamic rope before and didn't find it too bad.
once your weights on it its not much different, except as you say any sawing action but even thats not too big a deal.
what is noticeabble is that statics are usually more rugged in texture than, say, a dry treated climbing rope. they often too have a coarser mantle weave, so ascending a dynamic on prussic cord may not have the bite a static does.
on a dynamic ive done at most about 30m free-hanging(tho that was 9.2mm), but on a semi-static did 60m once for an evaluation (with a shunt and indian foot loop).
I prusiked a free-hanging half rope once, and wouldn't want to do it again.
Obviously protecting the rope from abrasion at the top is absolutely citical. Other than that, you're prusiking away for a surprisingly long time before you actually leave the ground*, after that it's pretty normal.