I have read several conversations where it was suggested to use a lathe head - excellent idea. However, I feel like being challenged seriously by this hobby, so I'm taking the proverbial 'plunge'. I just hope I have thought of everything. The spindle diameter is but a small, albeit most important, component of the build process. But, because it happens to be the most critical component, I keep second-guessing myself. I'm right now contemplating purchasing a 1-1/4" shaft from McMaster-Carr now and I think I'll go with it. It costs $23.39, but that's a small price for my peace of mind, I think. I'll just wait to see if more people might have some input.
Jim