Dan if you haven't made up your mind yet may I suggest you "buck the trend" and go 611.

Lately we have had RMD's, 511's, abd Basic 6's which all have approximately a 5 inch cutting edge.

Now there will be Basic 10's and Rodent 9's so something with a short blade or something in between.

I just love the handle on the regulator which is why I said 611.