Generating overlapping edges

I am after advice in making overlapping edges more quickly and easier than I currently do.

I often make hollow items that need to be cut in half for 3D printing and later rejoined, using an overlap edge to secure and prevent gaps.

I usually do it by creating a sketch on the outer half of the mating surface then extruding it.

Then I pull the two halves together and subtract one from the othe other and have my finished joining halves for 3D printing.

But this can get difficult when the shape is complex or when it is the result of a large number of sketches that are fused together. Sometimes the sketch is not exactly the right shape when I try to simply follow along the surface with a spline line etc.

I’ve tried to search for some more refined methods of producing the required objects without success.

Any advice from the forum?

Are you trying to create a connector between 2 parts? Advice could be different depending what the 2 pieces looked like. Is it something like this?

Or even more less complicated, you just need something in between to join. If that is the case some slicer software has a feature where you split a model you can add connectors.

Sorry my description was very poor.
I need to post an image of what I want to achieve but I can’t work out how to post an image.
Sorry but can you tell me how to post an image either from a saved screen shot or directly from Shapr page view?

Maybe a lap joint could work?