Add cap to loft

Changed the flat caps for flat domes.
2 questions still :
Is there a -hidden- node? I want to hide (remove) the circle at each end of the loft.
I use -points to curve- at the transition of straight rails: Loft produces wrinkles in these curves, twisting the longitudinal edges. Is there a way to tell it to keep them vertical. Say the topmost vertex at start stays topmost all the way to the end ? Like extension -Pipe Along Path- does.
https://creator.trimble.com/graph?layout=right&assetURI=whp:bfaf004c-b53f-4097-b5a6-a547dc8df5bd