Years back I had taken my timbales to my x-wifes uncle's house. Her other uncle, Hector who used to play bongo and timbal with Orquesta Broadway and Orquesta Novel (NY based Charanga bands) watched me play. At one point he came over and told me to hit the timbal shell in the middle, not at the bottom portion of the timbal. (LP timbales are designed in 3 parts). Since then I've always played that way.
Recently I saw the DVD that Santana's percussionist, Karl and Raul did. In the DVD he plays on the lower part of the timbal. I think playing the middle of the timbale gives a fuller sound and that the lower part, closer to the edge is thinner.
What's everyone else take on this?
Is it a matter of preference or is it important. I noticed in the video he bring up the "Batuka" bell part he uses in "Maria, Maria". He stresses the importance of playing from the middle to the edge, and not just banging on the bell. If this be the case, then I guess where the cascara pattern is played on the timbal shell would be important too..right?

I think the center of the shell produces a cutter sound, but it is also a little tricky to play (I like to shoulder the stick) because you can hit the tonning lugs.