Sceadwian,
Using 1 oz copper clad board and 8 Amps and accepting a 20 C rise in temperature, the traces are 0.137 inches wide; using 2 oz copper cuts that in half. I am not inclined towards widening the traces much more than that. I came across a circuit that looked like the attached file, but I was thinking that a 0.08 ohm resistor might be a bit inconvenient and a little questionable give that the Vbe of the BC547 might not be exactly 0.65V. So, I thought that it might be possible to put some sort of voltage regulator in its place and force the FJAF4310 to do the work. If this is a ridiculous thought, let me know how to use a PCT thermistor in this spot so that the current does not exceed 8A.
DavidBear