Nanuk, in my eyes this question can only be answered by yourself, as we don´t know the settings of your mod/scenario. Besides the factors you posted, another big factor for lags in turntimes can be the number of units on the map, the question if there are preset cities on the map or if the cities all must be founded and what terrain can be settled. Even dumb settings in unit stats can cause considerable extorsions of interturn-times. So here are only some general thoughts about map sizes besides the question of lag times, that belong to the settings of the individual mod/scenario: a) Random maps: If a mod/scenario plays on random maps (no preset cities), each map size above 250x250 (depending on the percentage of landmass and settelable terrain) can run into the problem, that interesting parts of that map can not be settled, as the game runs into the 512 cities limit of Civ 3. Unfortunately the NCL-Patch (no city limit) seems not to work properly. At least in my test I run into memory problems of the game starting with city 543 and into a freeze of the game with city 557 (other civers came to the same conclusion about city 556 in earlier posts): https://forums.civfanatics.com/threads/ccm2-epic-mod.625812/page-14#post-15439319 https://forums.civfanatics.com/threads/ccm2-epic-mod.625812/page-15#post-15440681 https://forums.civfanatics.com/threads/ccm2-epic-mod.625812/page-15#post-15441099 https://forums.civfanatics.com/threads/ccm2-epic-mod.625812/page-15#post-15444062 b) Preset maps: Some great scenarios show, that even maps bigger than 250 x 250 are considered by many civers to be 'worth' longer turn times, among them Rocoteh´s WW2 Global and my graphical update of that scenario (WW2 Global Gold), playing on a 360x306 world map. These scenarios use preplaced cities on the map. I tried to use that map for a worldmap of my CCM mod with fixed city locations (but no presetting of the cities themselves) and fixed names for the cities, given by preplaced resources to those locations, but here I run into a limit of only 256 different resources allowed in C3C. An in my eyes very clever solution for a preset 256x256 worldmap with preset starting locations, but no preset cities, is Yoda Power´s Giant Earth Concept Map (256x256). Unfortunately for a combination of my CCM mod with this cleverly designed worldmap there is an interference in using the wheeled flag for restrictions of unit movements. In the Giant Earth Map this flag is used more strategically in limiting the expansion of civs, while in CCM this flag is used more tactically for more interesting use in combat (especially against 'invisible' land units). On the other hand there exist many great scenarios with 180x180 worldmaps, the most famous among them in my eyes is El Justo´s AoI. c) Micromanagement during the player´s turn: Another factor besides the lag in turntimes is the problem of loosing much time with the micromanagement of cities and units, especially in the later stages of a game. In fact in my testgames I´m frequently more annoyed by the time I´m loosing in micromanaging all my cities and units than by the inter-turn times of the game. An AI governor for those cities is not accepted by me and an AI general for the units even does not exist. d) The situation of a worldmap for my mod CCM: At present I´m experimenting with 'hybrid' versions (partly preset cities) of the 360x306 and the 180x180 worldmaps. I will also have a closer eye on Yoda Power´s Giant Earth Map (especially, if the movement barrier by forests can be replaced by something different). e) Nanuk the situation for your mod in my eyes: Nanuk, I show you here my thoughts about building a proper worldmap for my mod, but you must find the proper solution for your mod yourself. One thing is sure: Without Rocoteh´s decision to use a 360x306 worldmap for his scenario, there wouldn´t be many civers in later times, who love that scenario in that format. He did boldly go, where no other Civ 3 modder has been gone before.