With (3) 6AWG stator leads and the remote rectifier mounted a couple of feet away from the house batteries you can pass 200-amperes 20-feet with insignificant voltage drop.
House battery alt VR sensing is common on cruising sailboats but degradation of sensing voltage can play hell with a lot of stuff in an automotive system. At the least an overcompensation of falsely low sensed voltage can cause the ECU to go open-loop.
Remember, you can leave the vehicle rectifiers silicon and piggyback Schottky across silicon for the house rectifier. This usually yields an .8 vdc increase to the paralleled rectifier house batteries. Don't skimp on rectifiers! 70-amp DO-5 silicon paired with a 70-amp Schottky gives good safety margins. For class, triple the rectifiers by adding MOTOROLA MR-2535 AVALANCHE rectifiers which are the size of a 3-amp axial. Add a 470 and a .47 uf electrolytic cap on the OUTside of the rectifier housing. A brushless ball-bearing fan saves a lot of heatsink size. With 3-amp axial diodes, rectify two stator phases for totally automatic fan operation.
