Though the degree of cooperation differs between alliances, airlines alliance is more helpful for small airlines. There are three major international airline alliances namely SkyTeam, Star Alliance and Oneworld. One of the modern alliances is that formed by cargo airlines.
The top terminal should be connected to wire #18 (low beam), the bottom right to wire #17 (high beam), and the bottom left to wire #91 (headlight to ground). I purchased my lights from a local shop, but I found that Susquehanna Motorsports has a web page with competitive prices and a nice write up about the lights.
A relay only needs a watt or two of power to activate it. On the other hand, even many old-fashioned sealed beam headlamp systems' total power is over 100W on low beam (even more on high beam), which means they need over 10 amps of current.