I've only ever considered stainless rod. I'll have to have a play with it and see what I think. I've seen lots of home build's around the net that use threaded bar with good enough results for what I'll be looking for. Although I agree that there is a little bit of false economy in going this way, but if the funds aren't there then I'd rather get it going on threaded bar and see how we go than waiting until I can afford the better options.

The construction will be easy to disassemble and modify in the future.

Thanks again
Paul