FWIW, I've had mine wired up for a couple weeks. Pulled a lead from my driver's side headlight. The setup works great with the flyback diode, i.e. any additional delay on their turn off is going to be imperceptible to most.
Spent some extra $$$ and bought the Motorcraft WPT1321 and WPT1279 pigtails I saw recommended on FRF so I didn't have to cut into the headlamp wires. Those worked excellent except I had to trim one plastic orientation tab on one of the pigtails, once trimmed, fit was perfect and they came with all needed waterproof heat shrink. I pulled my lead from the driver's side headlight instead of the passenger side, made for trivial wiring routing to where I placed my relay box. R&R of the headlight was straightforward after watching a vid on what tabs need to be popped off.
Hey there. I could not find the pigtails you chatted about. Do you have any more info? I want to put a pigtail between my harness and my light, and then wire that to a relay for my light bar.