2 quick things. 1 copper wire has a positive temperature co-efficient that is when it gets hot it's resistance increases which means that while it "Looks" like the current is going up it is actually going down because of the increase in resistance of the copper. It's all right to use copper for connecting things as the rules that that into consideration but not to measure current with because of it's 3300 PPM positive temp co..
And 2. There are many "Logic Level" mosfets available, using a driver and a higher voltage Vgs mosfet is kind of redundant.
Bob
{Edit RKJ}