Making a polysurface conform to another

Just looking for suggested approaches on how to handle this.

I have to illustrate seamstraps that look like this:

Where (like this) the joints are flush and flat, it s easy.

Where the joints are relatively flush, but not flat, the FLOW command seems to work:

I have cases where the joints have a straight joint but the joint is angled, so the seamstrap would have a V-shaped cross section. What might be the best way to do that:

The worst case looks like this:

So I am looking for ideas how to go about these last two cases.