Before I say anything, I'm curious as to how you came about this configuration. Also kitchen lighting / electric work is so much more complicated than most other areas of the house, what kind of help are you receiving in this, or is it a DIY? How did you get to the conclusion that low voltage can have wider beam spreads? As far as zoning goes (or placing "lights on a single switch"), instead of trying to figure out how many lights can go on a single switch you should figure out what groups of lights you want controlled by a single switch, more practical than technical for now. For example, when you flip on a switch do you want your whole kitchen lit up? Do you want just 1 main light source on so you can see (which I recommend)? Will there be undercabinet lighting? What are you task areas? I can't actually read the RCP because it's small and... colored? The only thing I can see right now is "pantry". Where's the sink? Across from it? *shrug* I have no idea.

bump

Sorry - I didn't notice the one response until after I typed in the bump. To answer khatam:

* I have an electrician doing the lighting install and a designer is helping on an hourly basis - but I'm not so confident about either of their detailed lighting knowledge.
* beam spread - I just read about low voltage having more bulbs w/ more beam spread options when researching low vs. line voltage on the internet.
* zoning - I'd like all task areas to be lit up together if possible and if we have ambient/center row lighting - then I'd like that to light up separately. The color coding is my best guess on how to divide up the zoning.
* yes, there is undercabinet lighting planned and wired
* Main sink is on the left "wall" (looks like a double sink); prep sink is on the "top" wall where the blue square box is.

Oh my goodness - noticed Plan B didn't post correctly! Here it is:

As far as I can tell the designer doesn't have too much lighting design knowledge. Are they an interior designer? The electrician won't be able to give you any information on placement, but rather be able to wire everything up.

Beam spread all depends on the type of lamp (technical term for lightbulb) is used, and nothing to do with your line voltage. I highly recommend line voltage.

You should be able to zone it how you would like, but I recommend having different switches for different tasks. Or even areas. Your undercabinet lighting should be separate from your kitchen lighting, this will not only help you on your lighting bill but will give you way more control. Also, I'm hoping with all this work you will actually have dimmers. Please remember that if you're using compact fluorescent you cannot use a dimmer, unless you have a ballast that supports it (very expensive ballasts).

There seems to be downlights all over the place, am I right? You will want to make sure downlights are 18" away from the wall.

Try to follow your contractor/electrician's advice as far as "how many lights can go on one switch".

To me it seems as if you're trying to turn all the lights into task lights, as oppose to indicating task areas. A well designed kitchen is well lit, however it doesn't have to be lit up like a ball of fire. I would love to give you more details, however I really can't read your plans very well. Perhaps a bigger size?