Porter Edun, Thanks so much for taking the time to impart this valuable knowledge complete with photos! Much appreciated, thanks!

I like your light fixture choice. Very pretty. A general rule is to measure the width of your island and subtract by 12. You want the glow of the light to land at least 6 inches from the end of the counter. Caroline on Design has a great visual that can help you. If you are only doing two I vote for the larger size. My personal preference is to have my lights hung a little higher than the standard rule. You need to see what works for you. Maybe a lighting expert can chime in to share what they think would work.

Ideally, you will want the space between each pendant to be the same as the width or diameter of each fixture. For example, if you have 18 inch pendants, the space between each fixture should be 18 inches. This rule of thumb remains true, even if the pendants are hung at staggering heights. To determine the appropriate size of your kitchen island pendants, follow the steps below: Measure the length and width of your table, kitchen island, counter, bar, or desk in feet. Subtract 12 inches (or 1 foot) from each of these measurements to ensure there is 6 inches of clearance on all sides of the fixture. Take the remaining measurements in feet and add them together. This number is the approximate width allowable of each pendant. To determine the allowable number of pendants over your desired surface, take the length of your table and minus 12 inches and then divide by any number under the maximum allowable width (as determined in the previous step) and divide by two. This number is the approximate number of pendants that you could hang over your kitchen island, dining room table, or counter-height bar. So I'm getting 18 inches is a good size. But my math may be off

Lucky, my kitchen ceilings are 12 ft. I'm going with two pendants, and I prefer they be a wider diameter. I hope to find some to warm up the kitchen. The 24" tile is soft gray, the perimeter cabinets are white, the island cabinets are soft gray, and the hardware is satin nickel. (The builder's design center had no brass options at the time.)  In the adjacent great room, there is a white sectional, colorful rug (blue, orange, beige, teal, gold) a brushed silver buffet used beneath the tv hanging on the wall, dark coffee (metal) and end tables, and a whitewashed sofa table with orange lamps.  The kitchen is so stark. It needs pendants that make a statement without being flashy.