I need to read the story fully later but if you just want simple lights the yellow from the mag should be highest output so just connect all your lights, head, tail, instruments to the yellow via a switch but with a 6volt ac regulator involved. Have switch so it stops the yellow before the regulator is involved otherwise the regulator might overheat trying to dump all the yellow voltage. Here's an example. Not sure why they say 6-12-24 volt as it'll stop voltage at about 7-volts normally if your mag has the capacity which it should have no trouble. Just the first sample i could easily find but they'll be up there somewhere cheaper than that. Maybe not cheaper now i look. Think that was cheapest i found.
www.aliexpress.com/item/1005009349259663...%7C_p_origin_prod%3A