>What do you use it for?
In normal games, in my experience, almost all characters are 3. What I do is:
1. Double the turn length.
2. Double the number of actions, so 2 SPD has 4.
3. Insert .5, that is 2.5 (which will have 5 SPD) and 3.5 (which will have an 7 SPD)
4. Give a post-6 recovery.
Basically double the number in a 24 second turn.