I have 15 4" cans in my approx 22x20 kitchen, some are in the 9' trays, some at 10'. The lumens is 650 (4000k), and it has been great...much better than my previous kitchen.

Thank you for the info. What are 9' and 10' trays? Are you talking about ceiling height?

Yes, I have a tray ceiling in my kitchen...I have the 4" cans on both levels, no noticeable difference in the light that they give ;) You didn't mention your ceiling height which I why I included it.

I wonder if you need different placement if you have no uppers. Our lighting plan has the sink recessed can placed over the center of the sink--that is, in the middle of the countertop depth. Because there will be no under cabinet light to counteract the shadow your body throws across the counter. If you have no uppers, and no under-cabinet lighting, maybe you need mid-counter overhead lights across the whole perimeter? Hoping one of the pros will weigh in on this to help you.

That's exactly how mine is. I only have 1 "real upper cabinet" (with UCL, as well as my open shelves which have channel UCL) and my cans shine the light to the middle of my perimeter counters...close enough to the walls to wash them nicely. I measured, my perimeter cans are approx 18-19" from the walls (again, no uppers in that area).

On our area with no upper cabinets we placed the recessed lights centered on the countertop. We have 8 ft ceilings. We installed 540 lumen lights about three feet apart. This seemed to be more than adequate based on the recommendations on the packaging. But I kept finding that I wanted more lighting when I was doing meal prep, so we switched them for 800 lumens instead, and I’m much happier. My SO says it’s too bright for him, but he can use the dimmer :)

Our ceiling is approx 8 ft high. 

I guess we'll just plan to have upper cabinets so that we can have under cabinet lights. It was a bit of a toss up as to whether we wanted to backsplash tile the entire wall vs the cost of at least some uppers. There will be an open shelf above the window above the sink so I think we can do some kind of recessed light within the shelf itself to better illuminate the sink area.

And I guess we will for sure be going with higher lumens than the 500. Thanks everyone!