An original-equipment stovebolt ammeter is about as accurate as driving finishing nails with an 8-lb sledgehammer, so why (with one notable exception) would anyone care if the shunt is totally accurate? Put any sort of shunt in there to keep the meter needle from going full scale in either direction, and get on with being anal-retentive about a thousand other things! If $5.00 worth of heavy wire is going to keep anyone here from eating regularly, why are they tinkering with old trucks in the first place?
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!