Cabin Fuse Box - 7.5A Tail for powering BD S8 Backlight

Hello - wondering if anyone has insight or experience in doing what I have in mind:

I have a BD S8 40" (white) that is connected to a dual switch (white / amber) that controls the amber backlight and white light. I plan on getting another BD S8 30" (amber) with the intent of using the same switch to control the amber light. I then plat to use a fuse tap for the amber backlights for both light bars, and tap them into the tail light. Note I plan on using the 64-0122 harness which has four wires:
Red connects to the 12V source
Black connects to the ground
Green is for the amber backlights
Yellow is for the relay

Question:
1. Is the 7.5A tail light fuse always hot or switched? I'm hoping for a tap that only goes on with the headlamps / parking lights and ideally within the cabin fuse box.
2. Would this wiring diagram work on the switch side:
Dual switch has five wires:
Black for ground; connect to black wire (from the two light bars)
Red for battery; connect to red wire (from the two light bars)
Blue for relay 1 (upper /amber switch); connect to S8 30" (amber) yellow wire
Green for relay 2 (lower / white switch); connect to S8 40" (white) yellow wire
Yellow for switch backlight power; connect an add-a-fuse

The green wires for both light bars will be connected to an add-a-fuse and ideally tapped into the tail light fuse.

Note while a switch controller would work better, I don't plan on installing one right now. I also don't have any spare OEM blank slots for more switches. I do want a reversible solution.

Would this work / make sense, and if it doesn't, what's a good alternative?