I can borrow a decent sized 360, good thinking! What about paper crumble as a constituent part? I can get hold of as much of that as I want, from virgin pulp and has a surprisingly low C:N ratio when I worked it out from the analysis supplied ~85:1
Paper crumble would work as long as you balance the C:N ratios, but be careful as you would be composting industrial waste materials and then you are in the realms of permits and planning, bio-aerosol risk assessments, odour management plans etc etc, oh and concrete and lots of it.
At a previous company we used to compost sewage sludge and woodchip and to blend it we used a rear discharge muck spreader with composting doors on which did a very creditable job. The doors were set at right angles and with a very slow forward speed saw a very nice windrow developing. Temperature increases were large and quick.