Well, generally the older the mexican the cheaper it is. But you might as well buy it new. I would go with a standard Strat with locking trem.

If you want to split the coils on the humbucking pickups then your going to need to either install toggle switches or push/pull pots. The push pull pots can be substituted for your 2 tones and volume control. Meaning, you can have the tone controlling tone as well as being able to move up and down to control how the humbucker is going to sound. I think you'll need DP/DT push pull, 500K pots. The DP/DT I am sure about, but the 500K I am not. I think it is preferred that either volume or tone use 250K and the other uses 500K. Check that with a guitar tech.