Loom conversion counterbalance to countermarch

My loom is a 4 shaft counterbalance loom but in order to weave more complicated patterns and fabrics I've decided to increase the number of shafts to 8. Whilst it's possible to have 8 shafts on a counterbalance loom, there are limitations and so I've decided to convert the loom to a countermarch loom. So I'm currently building (from scraps and an old table) 4 pedals, 8 lower lams, 4 upper lams, 4 shafts and the countermarch assembly with its 16 levers. There's not much information on the web so I'm working from photos of countermarch looms and my own mechanical knowledge.