Okay why did you not have a control when you ordered thme I hate indor shutters so I am not much help but you need to talk to the place you got them from.

Firstly, they are wooden Bahamian shutters which my carpenter custom-made for my house in the Caribbean. He has told me there are different ways to keep them open, so I am simply looking for helpful advice before choosing, versus negative criticism.

I'm assuming these are outdoor shutters. A longish hook and eye screw would keep them open. You could put eye screws at intervals up the side of the shutter to vary the angle. Depending how wide or heavy the shutters are, you might need fixings on both sides of the shutter.

Depending where you are, you should be able to get proper shutter stays online. You can get fixed length or adjustable.

I appreciate your kind help, however I meant the individual louvers, wondering what the options are for keeping them open without a central bar that pulls them up and down (I am equally wondering if such a bar could still be added?).

I'm not sure I can help Rachel. I've only seen Bahama shutters with fixed louvres. I assume they are not fixed and that you can move them by hand? If so, then I imagine you could add a central bar. It would probably have to be custom-made, so that it fits the spacing of the louvres on your shutter. It is difficult to say for sure without seeing or handling the shutter. Can you contact the carpenter who made them?