Tim here.
Dave, an easy way to retin your tanks is to find an old fashioned radiator repair shop with a tinning bath. Yes , copper plating is worth a try, altho may make parts too large for reassembly if too thick. Bob Harris in Canberra , Australia has a 23 chief ith a copper tank plated tank. The original as wafer thin with many rust holes, but he restored it to a working tank by copper plating, soldering up holes, copper plating etc again and again. He had a friend with a commercial copper plating shop, it ould have been very expensive otherwise.
Ziggys tanks are probably made in India, but the ones on ebay are direct from an Indian maker with no quality control at all. I have seen several that will not fit in the frame at all, and several that have mounting holes in rong places. Ziggys ones are usually useable , I seal the gas part of the tank before going any further.
If you are convinced your tanks are not worth using, send me one for free to play with :)
