It should be simple to solder to CN7. Are you using a buffer board between the radio and the dongle? You should, it will prevent loading down of the IF signal.
Once you get HDSDR installed, you have to set it to read an IF output, not antenna input. You then have to set the IF frequency to match that of the TS-950S, which is 73.050 MHz. Once you do this, you should see signals on the HDSDR screen.
Next step is to fine tune the offsets for each mode.
Once you get to this stage I can help you out, if needed.
Max
VE3TMT