I've got a track system on which I'm putting some WAC 802 Low voltage fixtures which take MR16 bulbs. In an area along the track I'd like to use them for generalized lighting. I'll be using an Ushio bulb with a 38 degree beam angle.

With an 8 foot ceiling, how do I calculate how far apart the fixtures have to be so they overlap to give me generalized lighting?

Here is a link that might be useful: The WAC fixture I'm using