I decided it would be dangerous to start cutting wires and connecting/splicing wires before I had a solid plan for how the wires would be routed so as to have known wire lengths to deal with. So today I put fasteners on the firewall, mocked up standoffs for the engine mount and ran the wires through sleeves to make everything very clean.

I have attached a photo showing how my mentor used hose and high temp zit ties for routing wires

I will use this method to make standoffs from the engine mount, here are my temporary attach points to get create my wire routing.

Attached are photos of the routing and sleeves I am using to keep thing clean looking.

The above (last photo) will have the red/white/black wires spliced to the yellow/black/red wires and the sleeve will be slid to the left through the zip tie location. All zip ties will be high temp zip ties, the ones you see are GripTies that are easily removable.

I am trying to be as creative as possible to make things as clean looking as possible.