I use two as well - downs counter on the left hand and field placement on right hand. Been doing so for 6-7 years.
I use the field placement marker like this:
- Referee
- Left and Right are from my vantage spot as the R
- Index finger for left hash
- Pinky finger for right hash
- Middle finger for left upright
- Ring finger for right upright
- Around middle and ring fingers for between the uprights
- Around index and middle fingers for between left hash and left upright
- Around ring and pinky fingers for between right hash and right upright
- Umpire, Back Umpire, Back Judge, Side Judge, or Field Judge
- Left and Right are from my vantage spot as the U, BU, BJ, SJ, FJ
- In my system, the U's (or BU etc...) left hash is the R's right hash
- Index finger for left hash
- Pinky finger for right hash
- Middle finger for left upright
- Ring finger for right upright
- Around middle and ring fingers for between the uprights
- Around index and middle fingers for between left hash and left upright
- Around ring and pinky fingers for between right hash and right upright
- Head Linesman, Line Judge
- Closest and Farthest are from my vantage spot as the HL, LJ
- Index finger for closest hash
- Pinky finger for farthest hash
- Middle finger for closest upright
- Ring finger for farthest upright
- Around middle and ring fingers for between the uprights
- Around index and middle fingers for between closest hash and closest upright
- Around ring and pinky fingers for between farthest upright and farthest hash
It works like a charm and it's part of my routine; I don't even know that I do it anymore.