Hi Paul,
In my opinion an uncertainty of 0.02 magnitudes is excellent on this target. The uncertainties in the CRTS photometry in the VSS Circular phase diagram and other VSS observers appear to range between roughly 0.03 to 0.15 magnitudes, so you are doing much better.
The lower SNR observations are still useful as statistical data can be extracted from many observations, and they confirm U Leo is not doing anything different. Though as always the higher the SNR the better, so I am sure your efforts will be greatly appreciated.
Andy