For those lookup tables as part of my code, I'm happy to save these in the onboard flash using PROGMEM. I plan to use this external flash for logged data, but looks like I need to do some reading up on file systems, how to address certain bits of the flash etc etc. Any good reading links?
Going back to the quoted comment below, I do not follow the logic?
Please note that your going to end up coping everything to and from internal sram constantly so your not necessarily during yourself a favor trying to use offboard sram.
Surely that's not particularly a problem, as I mentioned before - PCs for example use external RAM. Surely it's better to copy to external RAM, than to not and then run out of internal RAM?