I always wanted a better setup than the leather check strap to stop the door opening too far. When you convert to one piece windows like I did, you run out of room where the stock one went. So spent several hours walking around a wrecking yard to find some that would fit between the glass and the side of the door instead. I was unsure of what length or shape I would need to make this work, so started with this one from a Kia Carnival.
The stock check mounts have a bad habit of ripping out of the A pillar if someone lets go of a door on a side slope or a gust of wind grabs it suddenly. So I drilled and tapped some thick flat to take the mounting bolt. I drilled three holes. One for the bracket bolt and one above and below it for plug welding the piece in place once I had lowered it down on a magnet and secured it with the bolt.
The check strap was way too long so just kept shortening it until the door opened the right amount. You can see also that it needed a curve in it to clear the glass as it was closing. I also made up a spacer from plastic to space it back further inside the door so the A pillar bracket could fit into the door when the door was closed.
Because I had to shorten it, the end would be too weak to take the force of the door swinging too far as the hole was drilled in a much narrower section of the strap. So back to the wrecking yard and found that ones off a mid 90's Kia Reo had the right length and curve I needed. Also the same bolt spacing and width of housing.
I changed the arm pin to a stainless barrel bolt so it makes removing the door easier. Also counter sunk the bracket to take a door hinge screw for clearance and used button head screws to hold the check strap in place. The biggest issue it solved also over using the leather strap is that now the door stays open!