SBT with USB-HD & SDHC setup question/help!

Howdy, I have a SBT in a location that is best served as is. I have the SBT connected to a USB 2.0 HD which is connected to a powered USB 2.0 hub before hitting the SBT. Sometimes it works great, a couple of times it has disconnected from the server which is of course running on the HD (TinySC/TinyLMS)

While I'm not sure what causes this (don't actually think I'll ever know either given the nature of it) but, what I want to know is if I reset the to factory new, get it set back up (with the digital output app) before putting any drive to it, can I use a say 8gb SDHC card, have it install the server software on it and then attach the USB HD where the actual library is?

would i possibly get better results by not having the TinyLMS on the same physical drive as the library? if so, is a 8gb SDHC card large enough for the TinyLMS or do I need to go 16 or larger?

keep in mind, where this unit is, I cannot use a PC or internet access so the above options are my only choice(s).

also, does anyone already have theirs setup with the TinyLMS on a SD card and the library on a USB drive and if so, how well does it work?

I'd like to thank everyone who responds to this thread in advance for your time in trying to help me with this issue.