Does the room get any natural light? Seems like overkill to me, especially when LED lights can so easily increase the light you need. Are they all to hang above a long work table? Usually can lights are placed 4 feet apart. If you place your pendants 4 feet apart you can probably only install three, especially if they are large. It sounds like a chaotic visual, IMO. Are you crazy about the lights and unable to make a decision? We'd have to see them and the room and the furniture in the room to know if it is feasible. Yes, there are rules, but they're not unspoken. Task lighting is one of them. Not all lighting in a room is overhead.

Confession. The room has tons of light from an enormous window. I saw a picture of what I want which I thought was a drafting table and now I think it's a dining table. And YES! I'm crazy about the way the lights look. I had no idea how far apart they should be hung.

Not sure if you just have a 4' desk in the middle of a 15x15 room. The inspiration room with 5 pendants for decoration over a long dining table sounds good though, but you should switch gears to thinking about an office. Lay out the furniture plan. I would recommend recessed lights in a general grid that can be flexible to any layout if you are not sure about seating, credenzas, cabinets, etc.

This is good advice.

Maybe you can split up the pendants and use them elsewhere in your home.