OK. Let’s try a different path. Forget about plugs. Plugs are bad, dowels on the other hand have much more flexibility. What is the difference? Plugs are permanently part of the model half you’re cutting. Whereas dowels print the plugs as separate objects and leave holes on both halves of the model being cut. Also, you will find that you will have to dial in the dowel - or hole - tolerances to make them fit. By using dowels vs plugs that process is much easier which will be obvious in step 3.
For this example I will use this low poly dog model I found on Printables. It’s a good example because it has a lot of overhangs so cutting it into smaller shapes will help with printing.
- Start by cutting the model using the cut tool and angle it
- Then click on the dowel tool and it works just like this. Place your dowels just like you would plugs
If you get this message, there’s a bug in the software. just click on reset and place your dowels again. 
- Now here is where the process is different from plugs. Once you click confirm connectors, the slicer will cut the part and then create separate objects that will be scalable and editable.
This is much easier, because if you rely on the slicer defaults you will likely find that plugs/dowels do not fit in their respective holes. It’s much easier to resize them as separate “dowel” objects and it also takes much less time to reprint dowels during trial and error.
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Some other tips and tricks
Tip #1: If you’re using a smooth plate, click on “place on cut” this will provide a much cleaner edge to plug your dowels into and if you decide to use glue, the smooth surfaces mate much cleaner.
Also, if you dial-in the dowels or dowel holes tight enough, you will find that friction alone will keep the model together by simply press fitting the pieces together.
Tip #2: Experiment with a primitive like a cube or cylinder that is small enough to print quickly. You want to do this for two reasons. The first is practice. However, the best reason to do this is to trial-and-error the dowel dimensions till you get the “just perfect” fit. 
Then when you’re satisficed, use those settings with your full model. I promise you, this will save your sanity. 
One thing you may run into. If you try to rescale the dowels on their own by seperating them using the (O)bjects tool 
, you will find that the Slicer won’t let you. It’s in my view a design flaw but in the scheme of things, it’s easy to work around. Just uncheck the model pieces and then scale the full model and reprint the dowels. This is an alternate way to resize dowels without the aggravation of having to go through the cut process again.
