Hi Walter - I'm not sure about 27" switches, but here's a video of my brand new LionChief GP38 #2085 backing very slowly through KLine O42 and Marx O34 tubular O27-profile switches. Beautiful! You have to modify the Marx switches (add a guide rail) to make them reliable for most engines - not just LionChief.
(The #2085 says minimum 31", so in my case I wouldn't try a 27" switch.)
On the forum you'll find important info that the center pickup rollers on postwar locos can get caught on the manual O27 Marx switch - and easy work-arounds like adding a track pin to bridge the gap. But again that has nothing to do with LionChief.
https://ogrforum.com/...7#154307984399793977