You should be able to do three panels in those windows up into that arch with horizontal louvers and fully functional. Your shutter maker just needs to line vertical posts up where you have vertical mullions! giving that center shutter something to hinge to. Here are a couple of similar windows I have done. It's a partial arch but it's the same concept with yours

I am in Australia but a weed is a weed and I agree with Design Solution Group, that I too just pull by hand, unless there are too many rearing their ugly heads, as is the case right now with Spring upon us. I mulch very heavily with wood chips or similar but the weed seeds still blow in from all over the place, so if you think by mulching, you'll have no weeds you're kidding yourself but the amount of weeds to deal with, will be, with good mulching, about 10%, so it's definitely the most important thing any gardener should do, especially, now that many of us have a ride on mower instead of a push mower, we tend to be quite extravagant with the area of garden we now have versus say 50 years ago. I have to say that for me, at this time of the year, I simply don the backpack or hold the hand sprayer, a little Zero or Roundup and a shield on the end of the spray nozzle to protect against drift, and I'm off to spray and I spend perhaps an hour and save allot of weed pulling by poisoning these weeds. If I tried to pull these same weeds, it would take me approx. 2 - 3 hours on my knees to save my back. Just to let the readers know also, that the chemical I've mentioned with Glyphosate being the active constituant, is very safe to use and in fact when my husband, a farmer, did a compulsory chemical handling user course, he learned that this chemical is almost safe enough to drink without actually doing that, safer to use than the hair dye we women use to colour our hair and is safer than a very popular diet drink that if consumed to excess can cause death. So don't be afraid to spray to help lighten the burden of excess weeds at times, less weeds means that the plant you are nurturing and has at times cost many dollars, doesn't have competition from the weeds for nutrients and moisture. It is also an interesting fact that weeds, like simple grass if it's in the wrong place is still a weed, puts out a toxin surrounding it's root system to try to kill its nearest rival to protect itself from peril!! I have attached a photo of an area of my still newish or young garden taken last spring, as I now have another rather large plant bed to the left of the picture. This area is the smaller section of my front lawn and I have also attached photo's of my bulb/flax garden beds, of which there are 5 up the driveway, an early photo of my small cactus garden and a garden area around my fish pond, also an early photo with the plants now quite developed. I honestly do not have allot of work even with all this area with the biggest job once a year being, having to pull all the dead branches from my 40+ flax plants. AND Watering during summer would be the longest ongoing job in my garden!!!

Because there is a lot of timber and dark paint in the room ( which i like) and because it creates a neutral background you could easily takes some risks. The problem with fitted plain and very light fabrics is the risk of stains showing etc. so I would choose a mix and match red ( not a blue red) in leather if you have the money or a blue could be good to match the painted area. Another idea is to have fabric covers in natural fibres like washed linen that can be removed and washed easily. Look at beach house styles for inspiration. Add colour in a new rug!

Can't resist saying something about sliding rugs, they all slide , I have all wool Persian rugs , Afghani rugs and machine made rugs they all slide, you either put a really heavy table on it or you get non slip underlay . As for feather filled cushions , it again makes no difference cheep IKEA ones are actually better then Coco republic ones , they all slide on leather sofas.