I wouldn't exceed 6" in diameter. Depends on your ceiling height as well. However, if it is 8ft or so I'd stick with 5 to 6" in diameter depending on your space. I'd select fixtures that work best for the space. If there is not a lot of other lighting in the space then you want open or clear glass lights. If there is decent light from cans or..... and you want down lighting you can select cones or similar in metal fixtures.

There is a formula it goes something like this: Measure the length of your island/table in inches. Example: 60" wide Determine how many pendants you want and the diameter of each. Add them up for a combined diameter. Example: 3 pendants with an 8" diameter. Combined = 24" Subtract the combined diameter from the length of the island. Example: 60" - 24"= 36" Add 1 to the number of pendants. (This accounts for the space between each pendant and the ends of the island) Example: Since its 3 pendants, this number will be 4. Divide your subtracted value by the number of pendants. Example: 36" ÷ 4 = 9". You’ll want about 9" of space in between each pendant.

Hi Lizzie, The bottom of the pendant should be at least 75-90cm / 30” from the surface of the island. Pendant lights should be hung around 72” from the floor to the base of the light fixture. Good proportion practice should be exercised when hanging lights over a kitchen island, with equal space left between each pendant. Approximately 75cm (this depends on the diameter width). Smaller diameters can support a smaller gap between each fitting. To help give a visual reference before installing the fixture, a clever trick is to hang balloons roughly around the size as the pendants, this will help visualize the space more accurately and help determine is the light will look right. https://www.mullanlighting.com/blog/correct-height-hang-pendant-lights-chandeliers/ I hope it works out for you! Your friends at Mullan Lighting.

From reference above. "Now we know you all hate it when we say you SHOULD follow this or that rule, so call this post the Guideline of Threes in your mind if you must. Because there’s a good reason that sitcom wasn’t called Four’s Company, or there weren’t six blind mice. And that same reason can help you create an interesting home that’s not just functional, but also has visual depth and satisfaction. It’s pretty simple: The rule guideline of threes say that things arranged in odd numbers are more appealing, memorable, and effective than even-numbered groupings. Three seems to be *the* magic number, but 5, 7, or 9 work nicely as well. The principle holds weight in interior design, to be sure, but also pops up in graphic design, photography, storytelling, etc… (so you know it’s really a thing). What is it about the odd numbers? Apparently, it’s just how our lovely brains work. For one, three is the smallest number that can be used to form a distinguishable pattern in our heads. Also, when you see an odd number of things, your eye is forced to move around more, which makes for a more interesting visual experience."