You can cut it back to a single tablespoon, but it will take even longer to rise. It might take as long as 4 hours, I’d recommend punching it down after 2 hours. It probably won’t quite double, though.
In cool weather I usually put this dough in the warmest place I can find, which is on top of the computers in my office.
I bought myself a Nutrimill for this Christmas past (mostly because I knew from tho old BC that you had one and seemed well pleased with it) so I was interested to read this blog post.
I am curious though, why you grind hard red wheat at the “low and course” setting. Because that produces, well, course flour. There may well be occasions when course flour is needed but most of my bread baking projects use a finer grind, closer to that from a commercial mill (although it never gets quite that fine).
Anyway, I would be interested to know what your thinking is.