The FAQ has some notes and suggestions about farming:
What kind of equipment will be required for dedicated farming?
Its not about farming the most coin, but about how much profit you make = value of coin farmed - cost of farming (hardware, connectivity & power consumption)
Which configurations will be most “efficient” in these terms is very hard to predict, but I think we know that in terms of yield (Safecoin volume farmed) rank will be the most important factor. I admit though that I’m confused about the meaning of “network average” in this context. I used to think this meant average rank, but I’m not sure.