[sushi_78]

The Pax seems like the easiest option for a very large space but the Komplement is another option. With the Komplement you can buy ready made glass panels. Alternatively you can get acrylic cut to size online. For flooring, a thick piece of plywood, sealed against moisture, should work well.

You could use a ramp - not too steep - to provide access to each half of the cage.

Separate areas connected by tubes are fine for Syrians provided the tubes are large and secure enough, and each individual area provides a meaningful amount of space.

In terms of Plastikote alternatives, I recently used Little Knights paint for a cage. It's non-toxic and pet safe. You can buy both large tins and 100ml sample tins (which work out cheaper than Plastikote).