Open viewings v individual appointments—What’s best for selling a property?

Individual appointments offer each buyer a private, scheduled tour of your property.
I’m putting my property in West Cork on the market so have lots of ideas swirling around. One thing that came up in conversation with a friend was about viewings. Should I choose open viewings or individual appointments? What’s the difference, how do they work, and what’s the best option to sell my property? My understanding of open viewings is that anyone can come in and look at my house at the same time as lots of others. If so, I’m concerned about my safety and also my personal possessions.