The last picture is the type of connections I use, thanks in advance.
I had the same issue and found these. I would recommend looking through the resources tab and read through the description of Spartanburg/firestone and cornelius to make sure you get the right kit.
I had ball locks to start with… I kept goofing up the connections. Went to pin locks and my faults were corrected… I did switch to flared connections from the hose to the connectors… Use a 9/16" wrench… See, now you can switch to either connector… There are threaded connections on the posts to the keg… And they aren’t all the same size and thread pitch…
Pin locks have 2 pins for the gas connection and 3 pins for the liquid connection so its hard to mix them up. Ball locks have no pins. Then there is Sanke …
The blue keg is a ball lock, also called a Pepsi keg. The green one is a pin lock, also called a Coke keg. Those are the two big companies that chose each style of course. Your black QD, quick disconnect is a liquid ball lock. The gas QDs are gray. Gray=gas black=beer. The keg should be labeled in/out and some have a dimple or a cut in the handle part next to the gas post. I would guess the dimple or cut is to figure our what post it is under bad lighting conditions.
There is no reason not to have both but will require more connections. The ball lock kegs are also a little teller and thinner than the pin locks so that might be a consideration.
Thank you everyone, I had been busy and then forgot about this. It sounds like the easiest might be to get ball and lock connections.