Easements will not hide an 042 curve.
There are four 031 & 042 return loops on my 3 rail layout either hidden in mountains or off scene.
0120" and 0148" curves are visible on the mainline between the mountains.
Eye level at a distance the Rail King trains are not that non scale in appearance. In fact because the rest of the layout's track is all two rail at viewing angles it influences a visitors perception. No one notices the GG track at first.
If you have a desire for broad curve consider going around the room with shelf benchwork.
Any island platform will constrict any curves.
True spiral easements developed with a flex track transition will only add +/-2" of width to a 180 degree curve.