Custom Root Locus Plot

I need to create a custom rlocus plot in the app designer which does not support the native rlocus command.

I used [r,k] = rlocus(sys) and grabbed the r and k vectors and used pzmap poles and zeros to plot up a custom rlocus plot.

However, I would like to plot the current gain of my system on the rlocus plot. Neither dcgain(sys) nor [z,g]=zero(sys) nor [a,b,k]=zpkdata(sys) seem to be giving me accurate answers, except for the most simple of systems.

Any suggestions on how I can get this done? Thanks!