Again, donkey = bad player. I don't believe there are specific playing stlyes associated with a donkey.... Well, *not* tight-aggressive. But even a good player is capable of making a bad play and "donking" off a bunch of chips. You know, like calling all in with T high, hoping to hit a gutshot.
Get it?
Playing at a full table, you'd want to move the VP$IP filtering DOWN, not UP. You are supposed to play tighter at full tables. I think I'm around 27% VP$IP at 6 max limit and 18% VP$IP at a full limit table. So... a "donkey" (in this case meaning very loose preflop player) might be 50% at 6 max and just 35 or 40% at full ring.
Lastly, YES! The most important thing is learning how to play solid, winning poker. Only AFTER you've learned how to beat the various styles of opponents does it make sense for you to target specific players. In the past, you've been very passive, which is a recipe for disaster if you are targeting maniacs.