In reply to your second question: right mouse click on your chosen light and decrease the light range. In reply to your first question it all depends on your system spec, what settings you have set in your preferences, I suggest NO dynamic lights,quick light mapping,No shader effects,medium texture(256x256). How many lights you have will also effect build time, if they are static or dynamic, how many entities you have, the area you are trying to light, all these factors are taken into account when you build your test game, and depending on what system spec you have will depend on how long it takes. A low spec system and I would suggest goin and making a cup of tea.
"Never figure on your poultry enterprise until the proccess of inqubation has been throughly realized."