Locating the best adjustment point for specific issues can be daunting. While the same basic adjustments are required by similar machines, sometimes it is easiest to make the adjustment in one spot rather than another.
The basic principle is:
Begin at the part at issue (hook, needle bar, cam, etc.).
Look for a collar or gear with two or more set screws. If a collar had only one set screw the gear is positioned over a flat on the shaft limiting its adjustment to back and forth along the length of the shaft. If there are two or more set screws, it indicates that the collar or gear is located on the round portion of the shaft permitting adjustment both along the length of the shaft as well as around it.
Also consider the ease of access. Example, hook stop position adjustment could be made on the hook drive gear, but it is hard to access. So, trace back along the drive shaft to the timing connection. This is easily accessed through a cut out in the bottom of the frame. This is the best position on this machine. The next machine may be slightly different, but the same principles apply.