You would be wiser to use Reaper audio package (it lasts forever in demo mode, you just have to wait while it loads up). Also download looper 1.be, this will allow communication between the two programs.
Now open reaper, insert your audio track. Now add another track this will be your midi timecode track. right click in the track control section and choose midi timecode, now drag the timecode to the length of your audio track. There are youtube videos on this for MPC.
Now set Obsidian to receive time code externally, in the midi section, select looper1.
in your cuestack options box set cue list to timecode.
I normally create 100 blank cues. and set in the heading learn timecode.
Now comes the tricky part, as you have to start the audio reaper track at the same time as activating the cuestack. each time you hit go , your time will be set for each cue.
if your cues are all off by .5 of a second, unfortunately you have to correct each cue manually as there is a known bug in the timecode format and using – or ++ for an entire stack corrupts the timings, and there is no undo function!!
It might be easier to adjust the timecode offset in the reaper file.