I’ve been trying a 29″ wheel in the front of my rigid bike recently that has 440mm RC31 forks. It generally worked well and was definitely more comfortable over the summer to the point where I felt it would have gone nicely with a short travel thudbuster. I’ve gone back to my 26″ wheel for the winter as it has a hub dynamo.I think I prefer the handling in the wet and mud with the 26″ wheel, it seems easier to control when it’s sliding around. I had the 29″ as low as possible with a flat bar and flipped stem and I’m now running the 26″ the same.
I had thought I’d get the 29″ rim rebuilt with the dynamo hub but now I think I’ll keep both as they are and swap them out summer to winter.