In a kitchen I always space the lights so they are 600mm off the walls unless there are tall units in the way. This will put the lights so they are inline with the front edge of the worktop. That way when the customer is working the light is over head and won't generate shadow over the work area. Any further towards the middle of the room and you constantly cast shadow on the work area. Try to keep the lights about 1m apart at most to gain an even spread. I'd also go for the Halers EvoLEDs too if you can convince the customer to buy in to them. The warm white ones are the best and use choc boxes and Wago connectors for a nice quick second fix. A chalk line or a piece of string is also handy to ensure the 2 rows of 4 are in line. There's nothing worse then a line of recessed lights that are as bent as a dogs hind leg.