Hi,
Unless you run out of space in the /tmp partition adding a USB for logging will not help with the space issue. For most the space issue is with the /overlay partition. There are two plugins that use a lot of space on the /overlay partition, DataMine and ALTUI. It may help if you remove ALTUI and all its files. DataMine can be temporary removed by the installation script in a way you will not loose any of your data.
If you store your DateMine log files any ware in the /overlay partition you will have to move those somewhere else.
If that does not help I would suggest to sit it out with support. I suspect Vera has a way to avoid this problem. If more need their (free!) support they may look more closely at the script for the next release. It looks they did try for this release, but missed one or two options.
Removing just one file too many can brick your Vera, and as I do not want you to point to me when that happens, I will limit my self to the above suggestions

@Quinten, can you restore a backup? If not, the main configuration file on your system got corrupted. There are five versions on your vera in the /etc/cmh folder, so you can try to rename one of those to the main one and see if that helps.
Cheers Rene