I'd definitely want lights spread out over a 12 ft island. I think multiple pendants have been fashionable for many years, as I know I put them over my island in 2000. I've actually noticed recently a trend towards fewer larger pendants/fixtures. At the end of the day, it's really whatever you like. But, you do need more than one light fixture in that large a space. Lighting standards recommend MUCH more lighting in a kitchen than a living area, since a kitchen is a working space. I'd really look for at least two large pendants, and more likely three. If you only do two, I think they really need to be BIG -- 12" or more in diameter, for sure. If you go with 3, you could get away with smaller ones. I did three 8" diameter simple pendants over my 7 ft island . . . My ceilings are 10 ft, and the larger pendants look balanced with the space, whereas I think the smaller more common pendants would look a little silly with those huge ceilings. Assuming you have tall ceilings since they are sloped . . . and knowing you have a gigantic island, I'd lean toward either two large (14-18" diameter multi-bulb) fixtures or three medium sized (8-12 inch, with one or two high watt bulbs). That fixture linked above is only a bit over 4 ft wide, still leaving about 4 feet on each end, which seems a bit much to me to leave without an overhead light (since presumably each of the bulbs will just be 60 watt or equivalent). I'd want two fixtures, about 6 feet apart . . . or better yet, I'd really want three fixtures, each about 4 feet apart (i.e., end of island - 2 ft - light - 4 feet - light - 4 feet - light -2 feet -opposite end). That's what I'd do anyway.

Duplicate posting. https://www.houzz.com/discussions/5795331/help-need-3-pendants-that-complement-livex-belclaire-6-chandelier

Our island is similarly sized, a few inches over 9x4. We went with 2 large pendants, the glass on the pendants is 20"H x 10"D. I'd say 95% of the time I prefer 2 pendants over an island instead of 3. We don't have countertops yet and it's still very unfinished but here's a pic to give you an idea.

It depends what they are made of? Glass, Metal or something else? If they are a heavier looking light you definitely should go with something smaller.