Make a jig for the drilling Ken. A piece of plywood with an L shaped piece glued to it, your stanchion goes in the crux of the L and is held steady. Make a plate out of thicker brass sheet, mark off your hole centres and drill through. This plate is then held on your stanchion with 'finger and thumb' clamp, then just drill through the plate, holes in the same place on every stanchion! Once holes are drilled, measure of length and trim before next one.
Wire for the rails - look for rolls of jewellery or craft wire in places like the Range, ebay etc. comes in 10metre lenghts of varying thickness, get the half hard, the soft is too soft and hard is too hard
thicknesses go from 0.2mm 0.5mm 0.75mm and 1mm.
It will have taken up a curl from the rolls it is sold in, trim off a length say 15 inches or so, hold each end in pliers and waft through a low flame, this allows the pliers to pull it straight with light pressure and remove any curl or kinks - job done! Its what I use for all my handrails.