Cheers. 
That thread got a little bloated so this is the working parameters:
Name: SpekPath: C:\Windows\System32\cmd.exe
Parameter: '/Q/D/U/C START "SPEK" /MAX "F:\Music\Spek\spek.exe" "'%_path%'"'
Just found a much more advanced Analyser called Sonic Visualiser (Link here) which plays files and the same sort of command will work for it like so:
Parameter: '/Q/D/U/C START "SONIC" "C:\Program Files (x86)\Sonic Visualiser\Sonic Visualiser.exe" "'%_path%'"'Help for it here: http://www.sonicvisualiser.org/doc/referen...trogramharmonic
Screenshot:
https://s19.postimg.org/mu7abahmb/Sonic_Visualiser.jpg
You can edit the preferences to display 3 Spectrograms (Spectrogram, Melodic Range Spectrogram, Peak Frequency Spectrogram) under the Session template tab and then delete all but the hz Spectrum one and save as a template and you're good to go. I've saved mine and attached it for your use.
hz_Rolling_Spectrogram.zip (931 Bytes)
Place this unzipped file in: C:\Users<i>yourusername\AppData\Local\sonic-visualiser\Sonic Visualiser\templates and restart the program. Then setup mp3tag to work with it in the options and voilà , Spek on juice.
To get fullscreen don't put the program full screen, just drag out the UI window handles to size, close & reopen the app. It should now remember the UI size until you resize it leaving out the \MAX bit in the parameter.
See attached screenshot to show how you can save the current window layout and set as the default:
hz_Rolling_Spectrogram.zip (931 Bytes)