what would i used to have the midi left hand recorded on one track and the right on another track while playing with both left and right hands 
 
i'm presuming some sort of midi filter based on midi key value on each track
 
i'm thinking this will make editing easier
 
thanks
 
 

Band in the Box way.
After recording the MIDI piano performance, go to Notation View by hitting the 8th note toolbar icon, then select Options from the top LH of the Notation View, in the lower center of that is a dropdown listed as transpose, hit the little arrow next to the dropdown and choose the Piano notation view. Below that is the area where you can enter the Split Point. 

There is also an automatic Split Point routine, see the Help file inside BiaB on setting that up if you like. I usually use the above method. 
Reaper
Keyboard Splitter in 
Try This
http://forum.cakewalk.com...x-adjust-m2749720.aspx
 

If your keyboard can transmit on two different MIDI channels based on a keyboard split, you can set up two tracks with inputs set to record only their respective channels.
 
Otherwise, you'll have to split the parts out after the fact by Cut-Paste after selecting a range of notes in the PRV by sweeping the keyboard at the left or using Select > By Filter.
 
And, of course, depending on the piece, it may not be possible to find a split point that cleanly separates the two hands so you'll have to do some more editing in any case.
 
To get perfect separation of hands in all cases, you'd have to perform on two stacked keyboards and record the ports to separate tracks.