In the meantime brokemoto, have you tried Tomix track? I’m running some now for a trolley line. I have 140 mm (5.5”) manual turnouts and it comes power routing stock. And you can convert them to electric with a kit... they do have 103 /4” radius curves as track, and they have 5.5 street track curves and straights. Can get it on Japanese amazon with 3-5 shipping. I like it a lot, better turnouts and better bridge selections... don’t know that I’ll ever buy unitrack again except the sj62s adapters required for TTrack Standards.