I ski @ 36. SO I'm may not be the most knowledgeable to answer. I can say that Connelly is working on a 34MPH specific ski.
I think the prophecy would work great at 34 as well though. Maybe a 34 MPH skier can offer their comments.
The whole concept of having a different ski for a slower speed is pretty new idea.
I get 3 or 4 at 35 off almost every set, and ride a 2008 Prophecy at 34 mph (with draft plates). I have loved it - it has been extremely comfortable and stable for me. I've dropped about 60 lbs since I got mine, so it's definately too big (I'm 162 lbs skiing on a 68" ski). I am planning on trying some new, smaller skis this spring, including a 66" Prophecy.
I took about 10 years off, and the ski technology has really changed. I've been reading and studying, and really don't know what to try. Certainly the 66" Prophecy, but perhaps a Strada, a Syndicate, and a Z7. Would like to try a Goode, but thier test program makes that a little impractical.