External SSD as primary drive?

[opinio]

Tried this - first of all I got an error message:
"Recovery partition restores can only be done on GPT partition maps."
So I quit recovery, reformatted the external disc, went back into recovery, tried again and it worked.. thanks! And it is really quite fast..
So I suppose I can now run applications like Lightroom off the external SSD drive, save what I am currently working on there, and then use the internal HDD as a backup and to archive old material as well, as retaining the boot partition for a rainy day..

Cool. Glad that it worked.

Up to you what you do with the internal. Personally I would used SuperDuper to do a full image back up each night using the smart update setting to the internal from you external boot drive. That way you have have a current OS if you want to use the mini stand alone.

Either way you may want to just run it for a week or two just to see if you are happy with the performance of the external before you make major changes to the internal.