I have a reso. single cone spider design. I don't understand or see any split. do you mean a crack? like in a break?
The saddle is in two peices?.. I've seen it all over the internet but not sure why..
My saddle is maple.. You know the but where the strings rest over on the spider
The spider bridge should have a tension screw that runs through the center of the saddle. It is threaded through the bridge and presses down on the cone.
There is a discussion on the Stew-Mac site about setting up a spider bridge.
Here is a link that has some discussion about the tension screw. http://resonatorguitarstore.co.uk/how-to-set-up-a-resonator-guitar/
I have a single cone-bisquit style, it does not have the split saddle or the tension screw.
Hope this helps.
Jack