Use the same number of panels as the number of windows. Line the stiles up with the mullions. Use an inside mount frame that is typically called a Z frame and do a sill cut on the bottom. This way the frame will sit on the marble sill and the sides and top will overlap the edges giving you a nice finished look. You can get a free ebook that explains all about shutters at this blog post. https://dressthatwindow.com/beauty-of-shutters/ another thing I would recommend is that you do what is called a split tilt. You will see that in this picture also. The tilt rod is made as 2 pieces so that you can open the top and bottom separately. This allows you to open the top for light and leave the bottom closed for privacy. Don't get Hunter Douglas shutters unless you want to over pay. Get that ebook and read it to understand the different types of materials and what is best. If you are somewhat handy you could easily install the shutters for these 2 windows yourself. If you are not handy, say yourself the frustration and have someone else do it. Good luck!

I love interior shutters (eagerly waiting for mine to come in!) and absolutely disagree with the notion that they are light blocking bohemoths. With the variety of options that they have today, you can find something to fit lots of different scenarios. My house has a ton of great natural light, and I'm going to be preserving a lot of that by getting 4" louvers, which, when in the open position, let in lots of light. You can find shutters that open completely in a variety of configurations, from single panel to two panel (that open in the middle to each side) to bifold, which are popular for those that will be opened frequently as they take up less space on the adjoining wall. They also make them where you can open the top and bottom louvers independently of each other, so you can leave the bottom closed for privacy and the top open for light, and also open completely independently of each other. You may have some windows that you feel will stay closed much of the time and get a single panel for those, but two panel or bifolds for windows that you may want to open more frequently. I sound like a commercial, I know, but I really do love them. They are definitely a particular "look" and so obviously won't appeal to everyone, just like any other design style won't appeal to everyone. But for me, as a person who really dislikes fabric and fussiness, I think they add a lot of character and charm. In answer to your question, OP, I think they will look fine with your windows.

Plantation Shutters have a traditional feel to them.. You do loose some window having them mounted inside or outside can make a difference... also how many panels you go with.. most vinyl can go up to 36, wide...

I do, too! I have the cutest little accent window in my garage, and keep two electric candles in it. At my last house, I had them in my dormers. I have these from Amazon, and they’re nicely bright, but I didn’t recommend them in your case because the bases look plasticky and cheap. In my window, you can’t see the bases (plus it’s in a garage), so it doesn’t matter. Let me know what you find!