Rectangular “pipe” applied to line pattern created on a sweep2 surface // orient problems

Hello, i am new to grasshopper.
There are many topics related to rectangular “pipe” problems and i have tried many suggestions but nothing seems to work.
It works with pipe command but any sort of rectangular section applied to those lines (with sweep1 or loft which is usually suggested in other discussions) has problems of orientation. Created surfaces(and rectangles which generate the surfaces) are not always perpendicular to the original surface, their orientation in relation to the original surface varies.

Eventually my goal was to fillet those created surfaces so that their edges match, if such a thing is possible.

I would prefer to do it in grasshopper but rhino is ok as well.

Any help would be greatly appreciated.
Thank you. (26.2 KB)