After much lurk-studying I opted for the voltmeter change and the MAD conversion in the harness. I changed the vacum guage for a tachometer and drilled the bulkhead connector for the #10's to pass through. I added an auxillary fuse block with four additional circuits, putting the Tach on one and the Voltmeter on one with 2 spares. One of the spares is for the gearvendors unit when the time comes.