When I was growing up, my mom made the best cole slaw. She spoiled me, in that I could not eat anyone elses cole slaw. She never measured, she just made a very sweet dressing.
I can share what I did, but like my mom I did not measure. I poured a bag of slaw into a large bowl. In a small bowl I began with about one cup or mayonnaise. I added in one tablespoon of vinegar and about a half cup of sugar. I tried it and it wasn't quite sweet enough. I added a bit more sugar. I drizzled half of the dressing on the slaw and mixed. I then added the remaining dressing and thoroughly mixed. I like a very sweet, creamy dressing on cole slaw. It wasn't quite as good as moms, but it was close.