Which Leagues To Load
When selecting which leagues to load alongside your own, it is always worth considering have the major nations loaded (England, Spain, Italy, Germany, France). Then, you must consider the nations where you may target for scouting purposes. Brazil is an obvious selection, with the country's rich history of producing football superstars. I also selected the rest of the British nations, and the Republic of Ireland, to give myself as big a player pool from the local region as possible.
Computer performance is a major factor in the amount of leagues you can/should load. Ideally, we would be able to load every single league, but restrictions due to computer performance come in to play. The more leagues you load, the more strain you put on your computer. If your computer is under strain, the game will run a lot slower. Ideally, we want a fast-flowing game. It is up to you, however, to balance between database size and processing speed.