I understand Mabo, so I've decided to paint them in white instead of red, according to my documents, it will make them more generic and less specific but its' accurate according to photos.
The Train of the Horse guard artillery was dressed mostly like gunners with common accessories.
Those short boots with red line and long boots with white line are for the horse guard artillery of 1812
So here is the modifications I've just made :
You will notice on the photo below (the same unit of horse guard artillery) that for the period 1813-1814 the red and white line on boots disappeared completely and this is what could make confusion, uniforms was evolutive during the Napoleonic period.