First I took the entire car apart including the seats.
Then I made the “T” wipers out of some .30 (iirc) brass strips, soldering at the joint.
To fit them flush you might need to trim this area on both sides, I used my hobby knife and a file to clean it up.
Install the wipers and check for fitment. Sand the truck or brass if it’s to snugg. Once wheels roll smoothly and still touch the wipers glue in place with something non-permanent. I had liquid nails so I used that without issue. It holds and peels right off when you screw up.
Layout the components, I’m going to work on fitting in some top seats next.
I dremilled two notches for the wipers, I’m sure a better job could be done but I don’t really care.
Once notched, filed and tested to ensure the trucks can turn freely, I covered the area in kapton tape.
I then soldered my wire to two more brass strips and taped them to the insides of wipers.
I sanded down the bottom deck where it fits over the wires and notched out some of the seats above the wiper, nothing visible, just made it smooth. I also cut the upper deck supports a little since they pushed against the decoder and cap.