I'm with Mark on this one. I carry my nails/washers, hammer, stencils and rag in a backpack. I also carry spikes and whiskers for when I am measuring on a cinder trail, or concrete trail. Can't drive back to split locations on trails.
I use the stencils to paint mile numbers at the nail/washer. Paint can is in a bottle cage, but everything else is in my backpack. I don't worry about the weight, as it is part of the process, to me.