Drywall taping garage question

As long as the stud spacing is less than 24", the irregularity wouldn't be a big deal. You could add a stud where needed (sideways if you need to clear existing wires or something) so the edges of all sheets are supported. Just cut the stud to length, then use 3" deck screws at the top and bottom to secure it where you need it. It's not structural, it's just support for the drywall.

Don't cut any sheets to width until you reach the end of the wall, so every joint is tapered edge to tapered edge. You can make marks with a pencil at the floor and ceiling where the studs are located so you know where to drive screws, or just use an electronic stud finder.

Alternatively, instead of placing 1x3 strapping horizontally on face of the studs, you could install 2x4 blocking "between" the studs every 24" or so (flat side facing out). Of course, this would probably be more work than just adding an extra stud where needed. We used this approach in our master bedroom so we could install T&G pine vertically on the walls, but it's more than likely overkill for sheetrock. The only potential advantage would be solid blocking behind the sheetrock for mounting shelves or whatnot.

Anthony