Machine quilting is somewhat tedious, especially when I'm doing cross hatching. It is really effective on some quilts but really boring! My patches are 2" finished and that was just a bit too big not to mark for quilting. I basted my quilt first and mark a little as I quilt. I really cannot imagine marking a whole quilt top first.
Not all my patches are perfect, but I'm pretty sure I've never made a perfect quilt. (Or even near perfect!)
I just put my 24" ruler down and start marking across the squares. I do not necessarily go in any orderly fashion. Mark a few lines, sew a few lines...
Hmmm, some of those markings don't look very square. Once I get it quilted nobody will be able to tell.