idlemarvel
Neither idle nor a marvel

I found this "Technical Tips" document on the LGB web site when I was looking for something else. It talks about all the LGB set track pieces and then has some example layouts ranging in size from 286cm x 187cm to 435cm x 235cm. Most of them are "roundy roundy" but there is an end-to-end and one with a reversing loop. What intrigued me though was that one of them was multi-level (page 9) in 360cm x 185cm space. It seems to descend the height of a loco (at least 25cm ) in about 3m of track, that's 1:12 by my reckoning. That would test the traction of your locos!

The pdf is here (German) https://www.lgb.de/fileadmin/media/lgb/service/FAQ/LGB-Technik-Tipp-201-LGB-gleissystem.pdf

The pdf is here (German) https://www.lgb.de/fileadmin/media/lgb/service/FAQ/LGB-Technik-Tipp-201-LGB-gleissystem.pdf