Steve,
The Tenmaster is a great knobby and for JT trails would be fine. It works as well as any thrown over in corners. The Mitas is the most round and most predictable trials tire, but you can't grab a handful of 450 with the bars dragging or you will be on your face. On the trails we rode 2 weeks ago, I had no problem with cornering. The slightest berm makes a big difference. In tight, slick, and rocky turns I adopt a more upright, brake slide pivot style which works well. In general if the trail is fast and smooth enough to worry about cornering grip, I don't need the trials tire and run the MT16/Tubliss which is very good as well. Another thing is the trials tires save me a fortune in knobbys, which get wasted in a few rides here as I'm sure you can imagine.
The 914s are great front tires too!