KateG you are welcome..BTW if onsite material handling is going to be a problem then
you might consider asking your Engineer about…

manofaus
Here's the index link for duragalv flooring System spans for joist/beams only
None of those brochures refer to Column support heights &…

That's a nightmare so many post seeing it's on such a slope, I'd be getting someone else to design a better subfloor that won't be so difficult.
I'd build two pier…

check out duragal flooring system. they have a design guide or technical guide for such things. 90 x 90 x 2mm is good for 4.5m. The cheaper you want to…