For control, I find which reliever and starter had the highest strike percentage. In 2017, it was reliever Pat Neshek 74.1%, and starter Clayton Kershaw 68.6% (69).
Then, I look at the pitch. Kershaw in 2017 threw 1432 4 Seam Fastballs. His strike percentage was 29.75% and his ball percentage was 28.98%.
So, I divide Strike % by Ball % and times it by 69%.
30/29 X 69 = 71 Control rating on 4 Seam Fastball.
Now, this formula is not perfect. Sometimes you get a pitcher that throws 10 pitches and 8 of them are strikes or balls so his rating should be 100 or 5. In that case, with not a lot of data to work with, I will go with the 74 for relievers or 69 for starters as the high rating and 15-20 for low rating.
Since control ratings only effect games you physically pitch and not games you simulate, I find the ratings a challenge. Pitchers with control ratings in the 80's or 90's I think is too high. In my current franchise in MLB 2009, I play with the Yankees and I have a reliever named Brian Bruney. His control is awful and he is very tough to pitch with because his control is so bad.
Now, Movement rating is subjective and everyone has their opinion on how to figure out that rating.
I made a chart back a few years ago and measured how much each pitch moved with the movement rating at 0 and 100.
For Example, a circle change with the movement rating at 0 still moved about 2 inches. So, I created a chart and if a circle change had 6.4 inches of horizontal movement, I would give it a 44 rating for movement. Same with a straight change. If a change up had little horizontal movement but a lot of vertical movement, same thing.
Sliders are another pitch that is subjective. I usually don't give Sliders a movement rating over 60. A regular Slider in the Majors usually breaks between 3-5 inches. If a Slider has movement greater than 6 inches, I give that pitcher a Slurve. (Think Corey Kluber)
Giving a Slider a movement rating greater than 70 I think is unrealistic and it looks more like a curveball than slider.
Hope that helps.