i have tried all of those methods plus some and i have concluded that if you have a tall enough drop in with a good smooth tranny, turf works best. If you have a short drop in (under 5 ft) i would advice a mix between Lattice fencing and Turf. For the mix, use lattice for the first 2/3 of the drop-in, then use turf for the rest. Lattice is really slick and gives a ton of speed (can sometimes use it dry), but its good to get some edge before you hit your rail, so for the last 1/3 use turf. Fencing works alright, but it isn't as durable.
For Lattice, get the white plastic lattice and its about $10 for a 2x10 strip, which should be plenty. Make sure you have plywood under the lattice to support it, so that it doesn't crack.
Good Luck, PM me if you have anymore questions.
Park skiing allows skiers to enjoy skiing without good snow and terrain. It is better to be a park skier then to not a skier at all. Most of these kids would be shredding powder if they could be. ~nomensteven