SuperDuper to combine a small boot drive with a larger external drive
 

I wonder if this is possible using the sandbox related parts of SuperDuper! I'm thinking it is but I need some help with the idea

I have a 128gb SSD in my MacBook Pro and have removed the DVD drive and replaced it with the original 500gig HDD that my machine shipped with. This works very well and I have shifted a chunk of my big data (iTunes library and various other large data sets) to the (now internal) extra HDD. At present 500gig is still big enough that I actually have a 128gb clone of my SSD drive in its own partition.

I was wondering if it is possible to have SuperDuper clone my 128gb boot disk into one partition alongside the single folder I have at root level called "External Data". That way if I did book from the HDD instead of the SDD it would look just as it did before.

I think I can do this with a script but I'm unsure exactly how. I can't Exclude the "External Data" from the backup because it doesn't really exist on the SSD. If I share a folder by that name, will that stop SuperDuper erasing it from the destination HDD at copy time?

No, you can't preserve a folder on the destination like that (unless you use something other than Smart Update/Erase, then copy, which I wouldn't recommend).