Hi Louie
I think you touched on the problem with your CV settings. I believe that is the 'constant velocity' in Mach3 ? (I'm not a Mach user )
I use LinuxCNC, and get the same effects for segmented curves if I use 'exact path' mode, where basically your path is doing a full accel' and decel' on each segment of the curve, which causes the 'shake'. I tweeked the settings to allow a deviation from the path, which solved the problem.
I have no idea how the smoothe stepper system works , or interprets g-code though , sorry. Maybe it doesn't understand the CV code that mach puts out (if it works that way) ?
In linux, the codes are G61 and G64
Rich
My 1st Build (ongoing) http://www.cnczone.com/forums/diy-cnc_router_table_machines/134670-one_big_one_smaller_my.html