What is the best map size for going up in difficulty?
I have been going down the Steam achievements list trying to work on as many as I can, and I just recently won (kind of, just barely, with a small amount of save summing) my first Emperor game. I have mainly been playing on Tiny Earth type maps. During the Emperor game, Poland was making pretty much every single wonder, and he and the Incas were pretty aggressive towards me because I had a pretty weak military. I eventually was able to keep them at each other's throats and off of me by bribing them to war on each other almost constantly. They still really didn't like me though, but it kept them from sending their massive armies towards me. Poland technically ended up winning a culture victory one turn before I was set to be voted in to the world congress so I save summed to change that a little bit to be able to eek out the diplomatic victory.
My main question is the title. I like keeping it to smaller maps because the games feel a bit quicker, but I also felt like one runaway civ was able to build all the wonders, and spent most of the game picking on me. I'm definitely going to be playing a few more games at Emperor with larger maps, to be able to have more civs that I can be diplomatic with while being at a constant state of war with another to build up promotions. Plus it's more civs that can build wonders to keep one enemy AI from building all of them. But how many is too many to be manageable? Is standard going to typically be the best map size for learning higher difficulties?
I have done a lot of looking around at some old threads discussing map size, and it seems like everyone has their own opinion on their favorite size for their playstyle, but a lot of them specifically say they don't play at higher difficulties so I'd love to get some input from people who are constantly on immortal/deity.