Why not use all thread rod that goes through the width of the wall and is nut and washered from both sides?
Fish plates, or through wall bolting, does not restrain the veneer in both directions. Wind loading on the veneer creates a suction or compression force on the veneer. The intent of the ties is to absorb theses forces and transfer them to the base structure. The ties are to be stiff enough to limit veneer deflection which will limit cracking. Through-bolts only keep the wall from further separation and do little to function as an effective wall tie. They become a maintenance issue and an obtrusive projection from the face of the facade.