Hello,
We'd be happy to help but we would like to see a photo of the adjustment screw you now have to determine the best replacement option. Thank you!
Your type of screw with the "Fillister Head" reminds me of the type used with the 84-074 patio screen door roller. Unfortunately, we do not carry this type of screw. You would need to check with a hardware store in your area to have them match yours to the correct replacement.
The gap that you mentioned sounds like it may be an issue with the wheel adjustment. As for the placement of the wheel, it might be best to install the roller with the wheel toward the corner if you are able to. That would help balance the door with the wheels positioned further apart.
