Have a look at how its done in the factory!!
Its not that easy 10 feet in the air, but its still not too tricky as the hard work has been done off site....pre fabrication in the factory
You can see the insulation is built in, no air gaps so ZERO chance of condensation
If its not the best it would take some proving, fitter friendly with all the benefits of aluminium systems ( without the aluminium) ...No house / extension roof I ever saw was made of aluminium!!