Hot Tub Base for Overhang?

[rossyl]

I'm installing my hot tub on this raised section of patio. The slabs are laid on a full bed of concrete.

The hot tub will overhang this raised section by approx 300-400mm.

The height of the overhang to the patio below is 85-90mm.

What is the best way to create a base for the part of the tub that overhangs?

Loose laid concrete bricks, with shims, and gravel in between?

A treated wooden frame, with gravel between?

Any thoughts.

Thank you