The "fat" black wire that is in the dash harness connector that connects to the ignition switch is labeled in the FSM is Q-12BK does not connect directly to the fuse block on the back side buss strip. There is an internal splice that combines this wire, along with wires feeding the turn signal switch D1-18K, the voltage limiter input G1-18BK and the wiper switch input V1-16P. All of the other devices that are not receiving power that you mentioned in your first post come from fused side of the ACC buss strip.
You could narrow down your search by seeing if your turn signals and wiper are working. If they are, it is pointing towards your fuse block.
Just curious. We all know that M&H does not provide the correct 70 fuse block on their 70 dash harnesses. Perhaps, did you remove that fuse block and use the correct 70 fuse block from your old harness? If so, pull the fuse block away from your bulk head connector, then disconnect the "fat" black wire Q2A-12BK from the back ACC buss strip and see if you have power on that wire.
Jim