That should be enough to give you forward and backward synching: shift-command-click for pdf=>code, and control-option-command-o for code => pdf.
In addition, there is the excellent "Latex Watch" Command (bound to ctrl+cmd+w on my machine) which will automatically update the PDF upon a save (which you can set to automatically take place upon TM loosing focus in the TM preferences). In this workflow, you only need cmd+tab to update the pdf and switch to Skim but it assumes that you are already viewing the appropriate section of your pdf.
Best, Jonas