Korg Poly800/EX800 Users

Hi, I'm in the process of setting up a PCR30 to control my HAWK 800.  The easiest approach is probably just to assign each knob/slider/button a CC# to control corresponding parameters right?  I'm relatively new to this as well as using sysex and NRPN.  Now the real reason for this post since I sense there's alot of knowledge about this here:  This is not really relavant for the HAWK 800, but for other synths, how do you assign  negative to positive values to a control knob/slider,  for example an OSC waveshape with values -99 to 99 ?  In the PCR editor software, there's a "free message" field where you can enter a command whether it's sysex, NRPN etc and substitue the Data entry part with "DT" where you can specify the range.  Sorry to ask here, but I've been searching all over the net and can't find the solutution.  -Frank