There's a few ways to do this in S3D right now. I've used the "stop printing at height" option in the Advanced tab a few times. That lets you run a print that stops at a certain height, then you can insert your part and then run the rest of the print if needed.
I've also used their scripting which can automatically insert a pause command at a specific layer. For example, insert an "M0" command right before layer 50.
So both of those methods are pretty easy without needing to multiply anything
