Personally, and as a CFII, I would caution against using SVFR as a means to depart an airport being enveloped by fog. And I wouldn't use it to file to one airport, cancel, then scud-run 7 miles to home base.

Its hard to justify a SVFR at all. Yes, perhaps medevac flights or traffic watch. But really, not very useful for the most part. Go VFR or go IFR. At least thats the way I see it.