First, about the can trim. The "clear" trim (silvery) and "haze" trim (dull golden) are designed to reflect the most light while not producing much glare. The black baffle trim reflects the least glare. Personally, I dislike the look of all three of these. I prefer white baffle trim. I would rather put up with a little glare when they are on and have them disappear better into the ceiling when they are off. Secondly, the size issue. I chose 5" cans for my 8' kitchen ceiling because I think that size is the best tradeoff. The 4" cans don't spread their light very wide, so you need more of them, getting the "swiss cheese" look. The 6" cans are less attractive to me due to their large size. If you want fluorescent, you can buy a special 5" can made to hold the pin-base type of fluorescent bulb. That's what I did because I live in California, and a certain percentage of fluorescent lighting is required here as an energy-saving measure. As rjr220 said, fluorescents can't be dimmed, although I did manage to find some bulbs with acceptably an acceptably warm color, so I don't hate them. I haven't seen fluorescent floodlights made to fit in a 5" can, but they might exist. What I did over the sink is the 5" can with a PAR 30 50 Watt bulb on a dimmer, which is what I really prefer. These put out plenty of light, much more than the fluorescents do. In older parts of my house I have 6" cans that I put fluorescent bulbs in. They put out decent light, but I think the 5" size looks MUCH better. Juno is considered a better brand than Halo. It is supposed to be a bit better constructed, and has many more trim options. I have 5" Juno in the kitchen, and 6" Halo in my office. What I dislike about the Halo is that when you look up at them, you can see around the lightbulb into the guts of the can light. The Junos are not like that. The newest option with is energy saving are the LED cans, which Juno makes in 5" and 6". I don't know much about them because they have only become available recently. I think they are more expensive. You might want to check the lighting forum, also. Good luck with your renovation.

The size of the pots has little to do with the amount of light go with 3500 -5000k LEDS and you will need lamps either table or floor or better yet a mix.

The amount, placement, and style of fixture should be based on the room function, design, and level of the house. For instance, an 11x12 kitchen has very different requirements than an 11x12 office or 11x12 bathroom. 6" would typically require less fixtures and different spacing than 4", and is usually cheaper and less aesthetically pleasing to many people. And a basic grid of lighting is not the default solution for lighting.

You seem to be following whatever the electrician likes at any point in time. Typically in construction, you prepare a specification of the exact brand/model# of the fixture that a contractor is to price and install (e.g. Halo xxxx). Other times, you do the same then say "or equivalent," so the contractor can use any brand that matches that Halo fixture. Then a third take on that is you can give a general spec without a brand/model# and the contractor can use anything that matches that generality (e.g. 4", selectable CCT, >90CRI, white, integral). Maybe in your case you should go to a big box or lighting store, and look at recessed fixtures and see what you like. Then tell your electrician to give you those, or equivalent ones.