I despair every time I read posts like this. "Dovetail phobia", the irrational and totally unfounded fear of cutting dovetails by hand, is a blight on hobbyist furniture making!
And it's all so unnecessary. The wonderful thing about dovetails is that even if there's the odd gap they're still incredibly strong, in that respect they should be the beginners
first choice of joint rather than the absolute last resort.
Just an hour or so at the bench with an experienced hand and anyone, and I mean
anyone, can be cutting perfectly respectable dovetails with just a few simple hand tools.
And if you absolutely have to have a jig then forget all this complicated stuff that severely restricts your sizing and takes hours to set up, get a simple magnetic saw guide, such as David Barron sells,
http://www.davidbarronfurniture.co.uk/david_barron_tools.asp?pg=1&id=5
Even these are overkill, but at least they completely guarantee successful results for a complete beginner. What's more, they put you back in control as you can size dovetails to suit the design of furniture, ie graduated drawers, and you can have needle point, London pattern dovetails if you so wish, which is impossible with any jig.