Hi @dgleeson. I think you need to drirectly email Christoph Reinhart or Darren Robinson directly about this. I'm not sure if they will ever check unmethours. You may have a better chance to get a reply if you send this question to radiance mailing-list (I know we decided to give unmethours a try but here are the cases that mailing list will probably work better for you.)

Not the answer to your question but you may find Radiance's gandaymtx as a very useful alternate to gencumulativesky.