hi ,
You mentioned the hustler type of adjuster, can u please direct me to a picture of one as we both are aware of the max 2 adjuster faults .IMO the max ajuster is an average performer ,so yes i would consider others . [it was just easier for me to start with a pre made unit ]
The replacement for the timber would be say 1/2 inch HDPE or if it is not rigid enough a plastic sheet of some type . I have seen the recycled plastic logs they use under rail line tough flexiable weather proof, sheets available ??
Another idea is to use foam that is used in fibre glass boats . I am aware of it being f/glassed in [down side would be limited strength ]
If u use timber or equivilant on the floor remember its original purpose would have been
stiffness for added strength
required to be water proof unlike timber
The ""timber""' insert has to function like a false floor as it is fibre glassed to the main floor allowing eg rocks to penetrate the outer floor but still no leaks to the inside
tomo