I'm building a large wire harness that connects all added devices on the car. The harness is three sections and they all meet on the dash side of the firewall and connect to a relay and fuse block I call ECM.

Because of the amount of crap I'm stuffing in this car to be mounted, installed, wired, piped, connected and hosed: 3 stages of boost, 3 stages of water methanol injection, extra injector controller, fog lights, air horn, MSD ignition units, 4 gauges and sensors, LED status indicators, Solenoid Valves, Toggle switches, Push buttons, Rocker switches, Air pump, meth kit, fail safes, amp, extra speakers, 15 relays, 9 blade fuses, 3 Mini ANL fuses, 4 dials (variable resistors/potentiometers) and other stuff. I do not want to run individual wires or harnesses for each device, One large harness that unplugs at every device, plugs together between sections of the car (engine bay, dash, trunk), run trough the firewall using factory style rubber grommets, run along side the factory harnesses and can be removed easily.

So before I commit wires, crimp connectors and install them in plugs, measure and buy replacement potentiometers for the MSD dials.
I'd like to confirm that I'm not running to many MSD timing control units in a row, the wiring is simple for the 3 ignition units, white is factory coil pulse signal in, orange is coil pulse out except for the 6AL that uses orange for constant +12V to the coil.
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The MSD 6AL and Tach adapter mount under the battery on the front drivers side of the engine bay. The Timing control unit and Boost timing master are in the dash.
The coil signals path:
Factory ECU (Dash) ---> Factory Igniter (driver front strut tower) ---> Tach adapter T (from under battery) ---> MSD TCU (dash) ---> MSD BTM (dash) ---> MSD 6AL (battery) ---> Ignition Coil (drivers front strut tower).
Are there any issues with unit distances?