Having been unsucessful in dye tinting,many years ago I used to use a transparent paint put out by Testors mainly for model car use. This could be a little hit or miss affair as it was difficult to spray it on even. At a local hardware store I recently found a 200ml.spray can of .... plasti-kote GLASS SPRAY PAINT....... origin unmarked but distributed by.... Master Distributors Pty.Ltd. 11 Howleys Road.Notting Hill.Victoria.Australia.3168. It looks disaster when first sprayed on but drys completely transparent and even shade in about 30 mins.