I've got a window almost identical to the OP's, and have 2" wood slat blinds made by Hunter Douglas. The window was too wide for one blind, and for some reason I can't quite remember now now we ordered it with three blinds: single blinds over the outer windows and a double over the two inner--I think I thought at the time that the trim strips are wider between each outer window and the middle pair, although if they are it's pretty marginal. In retrospect it probably would have made more sense to get two double blinds. I have no problems with the slats lining up across the whole array, they look perfectly lined up both opened and closed. I replaced the casement cranks with round openers which are a pain to use, but do clear the blinds. Because the trim has so many angles we always have to do an outside mount, rather than hanging the blinds inside the casement. The blinds are tapeless and only have notches on the backside, so the slats do often slide out of position, especially with cats playing with them. We have the typical wooden wands for angling the blinds and cords for pulling them up. Do think carefully about the placement of those, I made a mistake on the left-most window--I placed the wand and cord on the left side, which looks better, but because of furniture placement it's a stretch to reach them. I'd definitely advise convenient vs. hidden. I don't mind the look of the wands and cords, though the breakaway plastic tips on the cords--mandated for child safety--don't like to stay snapped together. If the appearance really bothers you, why not look into the motorized kind where there's a remote to pull them up and down? I do find that they're heavy, and between the effort to raise them and worry that the strings will give way eventually, I only pull them up occasionally. Most of the time I just tilt them open. I mail-ordered the blinds and the wooden valance top had returns on each window. Since I was mounting three blinds and valances across the four-window array, I had to saw off the middle returns. To cover the seam I bought little wooden letters at Michael's for our last name initial and glued them over the seam. Silly, perhaps, but it worked. If you're custom-ordering the blinds from a local shop they might be able to order you one long valance, but I took the budget route with an on-line vendor. Of course you can always add a fabric valance, though I've never gotten around to it and prefer the clean look of just the wood anyway.

I installed 2" white painted faux in our sunroom & 2 bathrooms - similiar to your sizes - Since we have an old home w/lovely moldings I opted for inside mount - because the trim has graduated detail it took some doing to have them properly hang/operate and clear all the trim - Glad I had professionals do that agree w/gk about the 1" good luck

I've collected several from thrift stores, yard sales, etc. trying to get enough to do my rooms. Did not realize that there were different widths on the slats (duh). I put up one in my back hallway and then 1 in the bathroom. The back hallway looked so much better and then I realized that the bathroom one was 2" and hallway 1 1/2". I think you're on the right track thinking the larger ones are too big and will stick out too far. I'd see if I could find one first locally in both sizes and then try one out.

Johnmari, Thank you for sharing about the many variations on white. Now I'm a little worried. We really don't have $ to go for custom treatments. If I go with the white, maybe I should order, try one, and then understand I may have to return? Yes. Absolutely. That was JM's point and what I assumed (and shouldn't have) you already knew. You need to have a plan to check the color before you commit. Or, as Annz said, there are many other resources out there at about the same price point as JCP where you can obtain samples before you buy. My Lowe's for instance has a nice supply of take home color samples for blinds and plantation shutters. You mention a mix of mission and contemporary - again, either would work. Someone made the point the wood tones do not reflect as much light into the space -- that is accurate. If you have abundant natural light, might not be such a concern. But if you're having trouble deciding between the two, that factor is something to consider. Exterior - Again, either can work. It's a matter of your deciding which choice, white or wood, is going to fit best with the design and look you're marching towards interior as well as exterior. Maybe make a spreadsheet and list the pros and cons of each color choice to help you see which one 'fits' best at least on paper.