The ones you mention are the most common ones used by games (but note that a lot of games use either no scaling or a completely arbitrary one).
MDV 0%
MDV 100% = MDH 56.25% for 16:9
MDV 133% = MDH 100% for 4:3
MDV 178% = MDH 100% for 16:9
The 100% values are derived directly from the FOV value, so for instance a 90 FOV hipfire to a 45 FOV scope would be 90/45=twice the 360 distance. The different percentages are linked to the FOV type of games, if they use vertical FOV you will get MDV 100%, if they use a 4:3 based FOV you get MDV 133% (4/3) or MDH 100% for 4:3 etc.
My suggestion is always to start at MDV 0% and go up in these increments if it feels too slow. Then go to some middle value if the next step turns out to be too fast.