How to parameterize a shape that is composed of several pieces

Hi, All.
I got this form through a series of form finding steps, so the arch part is composed of several pieces.I try to merge the part as an integrated single surface but did not succeed till now. I used method as follows :1 mesh - mesh to nurbs; 2 push and pull a single surface to reshape, both of which take a long time without expected smooth surface.
So I would like to ask for some help from you proficient guys.
Any help or tips would be kindly appreciated!
20210309 back podium.3dm (1.4 MB)
Image is below

You can see that there are several component

How about try “contour” - " loft" then re-touch some shape with subd tools, after transforming mesh or subd somethings …

Yes, Beak.
Thanks for discussion :smiley:
I have managed to make it to stripes like below by contour and loft

I am not familiar with subD at the moment, and will continue to learn… :sweat_smile:
While I wonder is there some method that can make the frames like below