Yeah, I hadn't considered the possibility of a set of holes in the column casting sides through which one could insert a rod that would (also) go through an I-bolt in the weight. That would be a nice way to stow a weight to detension the chain. The downside to this approach is that it would make the dimensions for the head block far more sensitive which is a problem for me (not next to the machine with a saw and blocking at hand).

Anyhow, I look forward to the pictures, but it sounds like I'm going down a path in at least some semblance of the right direction.