Recessed lights are not like our old fixtures in the middle of the room. Those old fixture lights the counters well. Recessed can cause shadows which then require undercabinet lights. I jokingly say that the new lighting with recessed is a conspiracy by the lighting companies to sell more fixtures. You now need three types of lights.

To avoid the shadows pull the lights slightly away from the counter until the light does not create a shadow on the counter. To avoid you casting a shadow have fixtures to the left and right of where you stand.
I enjoy by 5" Commerical Electric IC cans from HD and CFL 3000k bulbs from HD (n;vision). The good thing about CFLs is you can change them to get a different color white and brighter bulbs, etc. A 6" can with an open baffle may reveal the CFL too much. I like them hidden with my halo 5001p baffle.
Ask the electrian why he is using 6" since 5" seems to be the current desire. You could go to HD and buy them and the baffles and have them on hand when he arrives and compare with his fixture.
HD (and believe me, I shop Lowes equally) has a cheap 3 pack of Flourscent light for under the counter with switches, GE makes the same thing (looks like better quality). They are both very thin. The bulbs might have to be changed to get the color white you want.
Have him explain how the wiring goes and ask him if you want to add more recessed cans, is there a way it can be done later.

I don't want to cost you money, but this might save you from getting undercabinet light. If you have old extension cords you can cut up, have him safely wire a can or two and move them around to test the lighting.

He might be restricted in some can placement because of wires and pipes above, so be prepared for that.

Just one person's experience. Certainly you will have different ones from me.
Good Luck,
Bob

Sorry, I was thinking he would be there tomorrow. Guess you have to go with the flow. Just watch how the wires are run. Draw yourself a diagram for future reference.
Bob

Electrician is actually here later today so still a little time for me to go to HD or Lowes. I can certainly use this advice. I will get the 5" that you suggest as your reasoning makes sense to me. I don't mind putting more lights in even if it is more costly to be sure that the room is well lit. I think I have just been put off by the whole undercabinet lighting as another thing for me to learn and understand. My electrician of all of those working on the kitchen is probably the least experienced. The cabinet installer will oversee, but is not a true contractor for this job. So, the electrician does not give as much advice as would be helpful for me. I think it makes sense for undercabinet lighting. I will do a search for it on GW. The thought did run through my mind, though, that maybe I should just do a couple of ceiling lights and be done with it! (Just no retro globe!)

I spent a year researching kitchen lights, in great detail. I even built my own light fixtures for T5 bulbs. I learned to do leaded glass and built 2 beautiful covers (got very favorable comments). But when I looked up I still saw flourscents long bulb fixtures. I wanted recessed because they are modern but my restriction was that my first floor kitchen is under two baths upstairs. Pipes and wires were running everywhere. I finally removed the 12' trim panels above my kitchen cabinets and cut holes in the ceiling . I pain stakingly measured every wire and pipe distance using mirrors to peer into the ceiling between each joist. After weeks I was ready to place the holes. I cut them because I did want to electrican to be resposible for a bad hole location.
The recessed cans went up. For the first time in a year I am happy with my lights. I wasn't going to put undercabinets lights in because my lights are placed so that I have good light on the counters. But my sister-in-law came in town and said, "You ARE going the have undercabinet lights, aren't you". GRRR.
Now, after playing with them I like the concept because I will use them when I want lower light levels. Example, when I wake up and it is dark, I may have an undercabinet light on only over the sink and where I make coffee, etc.
If you don't have the light picked out today, you could still have him wire for it. Remember the sink light gives off light and the stove gives off light. So you might put it where the area is dark under the cabinets. If you place the recessed cans out slightly from the counter you may have plenty of light on the counters.
Good Luck,
Bob
Bob

Bob, Thank you for your thorough responses. What an effort you went through to put in great lighting! Congratulations on that task! I think every aspect of the kitchen counts for something, that is why I like to research, but I kind of have several responsibilities at once, so my time is divided. Then, we are trying to finish this by the end of this month to at least have a presentable and useful kitchen. A call to the electrician, founded that he did have 5" cans, not 6. I am going to a lighting store now. I will ask about the undercabinet lighting there, as I do think it would be helpful at the base of the "U" shape of the cabinets, at least.