For a good quality dado set, look into finding a Dewalt or Delta set on Ebay or at one of the various small online tool retailers. NOT woodcraft or rockler as those sets have been discontinued and are no longer stocked in regular retail outlets. The Dewalt and Delta are identical and are made in the UK and as I recall, quite a good quality for the price at the time ($125?)
Because they are old stock, I'd venture you could source a set for $55-80 and it'd be the best money spent on a new dado set I'd think.
As far as soffits go, I'm trying to figure out why you guys would use pocket screws OR the Domino for such a purpose??? 2x framing lumber and 3 1/2" nails or screws is how they are done in the real world. Not as though they are subject to any stress. Man it had to take a huge amount of time pocketing that soffit together!
That's almost like cutting drywall with a TS saw, though I'll bet many here have done that!
JT