Micro batches tens to be 15 20 or 40 grams to target certain areas. You can scroll further up to see the mold and parts.I believe you have some good suggestions as to why this is happening. What is the size of this part and how big are these "micro" batches.
I've done more complex single molds. It's also a matter of prep working knowing where to pour the resin in and where to cut a seam line. I just wouldn't rule it out considering that doing a proper 2 part mold is typically harder.
Have you considered the silicone thickness to make sure it doesn't need a mother mold or jacket?
I didn't make mother molds I just sandwich it between two pieces of wood.