the best way to figure it out is using your own hand, put your hand on top of the highest part of the plant, with the top of your hand facing the light, if your hand is hot within 30 - 60 seconds then they are too close, if you feel the heat from the light then the plants do too.
Nutes depend on the soil u are using, if its organic then do some research on the grow guides and journals so you can make your own decision on feeding habits and what to use, try and find a grow that is similar to yours in the journals also..
If the soil feeds for a period of time then hold your nutes for at least 2-3 weeks, and then start with a very low solution of nutes and see how they react, start working you way up to the standards specified by the company if they seem to like it...