Second row heated seats

After getting into our Sienna Sunday morning when it was -14 degrees F. and the wind chill was -31 degrees F., even my wife thinks it would be nice to have seat heaters in the second row.

Installing carbon fiber seat heater pads in the seat cushions and backs and installing the switches on the inboard front corners of the seat cushion trim panels seems easy enough - except for removing/reinstalling those incredibly heavy "lounge seat captain's chairs with long-slide feature". I removed them once by myself and will never do that again without help.

The main challenge is how to route the power and ground wires for the heaters to the seats while preserving the "long-slide feature" without the wires showing and being subject to damage as the seat is slid from its front most to rear most position.

I have studied interior photos and parts diagrams for the Toyota Alphard Executive Lounge which has a long-slide feature for its second row captain's chairs (they are more like thrones!) which have power-everything ... recline, massage, footrest, table. The wire bundle for the second row Alphard seats appear to be inside the seat track channels in the floor. I suspect that the wire bundle for the Alphard 2nd row seats might be fairly large due to the many electrical functions and I'm guessing that the channels in the Alphard floor are deeper than the Sienna's to make room for it.

It doesn't look like I can hide the wires for the 2nd row seat heaters in the seat track channels of the Sienna due to their not being enough room and the possibility (or probability) that moving the seat would damage the wires.

What I'm thinking about doing is to run the wires for each second row seat heater from the front of the vehicle under the carpet and have them exit up through the carpet just aft of where the bottom edge of the retracted foot rest is when the 2nd row seat is slid as far rearward as it goes. I think having the wires exit at this position would allow the seat to be slid all the way forward with the seat heater wire exit point from the carpet then being just below the rear of the seat cushion. The arrow in the attached photo is pointed to just ahead of where I would slit the carpet for the seat heater wire to exit from below the carpet.

Any suggestions on how to route the wires or anything else on this project?

If I don't talk myself out of the project, I will use Dorman carbon fiber seat heaters since they seem to get the best reviews for reliability and function although they are pricier than most. Maybe I'm lucky that Amazon is out currently out of the Dorman kits although more will be arriving soon. Demand for them might have increased due to the recent weather.

If this project goes well, I might try to put seat heaters in the third row - outboard seats only. Routing wires into the third row seats should be easier since there are already wires for the power recline feature and I assume I can run seat heater wires alongside those. I would put the seat heater switches on the front outboard corners near the recline switches.