Yes, the larger the cross section and wider the sheet and the better the conductivity of the material then the lower the resistance. However at a certain point the difference becomes so small that it has no practical use. Thicker than a 10mil (about 30 gauge) sheet with 1/4 inch or more width of copper or silver and it really starts to get tough to tell the difference even with good measuring equipment. Past that point the internal resistance of the battery is a much larger contributor to voltage drop. I prefer copper for the current carrying paths and silver alloy for the contacts. The difference in electrical conductivity between pure silver (which is very soft) and copper is nominal for anything above 10mil thick with 1/4 inch or more of width. Pure silver is also not the best for contacts. Sterling silver is better for contacts, but an alloy with a little more copper and very small amounts of more exotic elements will tarnish and pit less. I prefer to use contacts made for comparable amperage industrial contacts in relays and contactors. BTW, most people don't realize that sterling silver (used alot in DIY) is actually slightly less conductive than copper.
