but was unable to hit upon what I was looking for. But, I know it's here somewhere. I have a Mega Colossal Rift planet that I want to have the highest amount of artifact production on. What artifacts should be used to accomplish this? Let's assume that I'm using 3 hyperforge Fabs (upgraded).

if you havent already do not use 3
I think that this is what you are looking for.

I would suggest one +24 at most, I only had 2 and I am already planning demolishing one to make way for better stuff.
Not a huge deal, but shame to demolish nice limited structures that would work well on other planets instead.

Only use 1 +24. There are enough 2 ratio/percentage arti buildings to fill the rest of the space with a few spaces left over to round out with 1 ratio buildings but meaning you'll have plenty of space for any released 2 ratio buildings.