What is the point in increasing the mast rake - other than tightening the leech of the spinnaker? Do you increase mast rake when you expect heavy winds on the regatta course?

Thanks,
Kai

Yes. Rake back for bigger breeze.

Spinnaker Leech tension adjustment can be made by altering the pigtail length on the head of the spin halyard. Rake is not typically altered to adjust spinnaker leech tension.