I built mine in about 6 hours including troubleshooting, perhaps a little more for paint drying and so on. I just worked on it a little after work each day for a few days.
I didn't have that good luck with getting SIDs and Wilba bailed me out in the end as I kept ending up with defective ones. As for whether he has any kits left, or whether he has any 6582s left you'll have to ask him directly. Failing that finding commodore 64s will eventually get you some working 6581 sids if you get enough of them, but finding fully working ones is a needle in a haystack, and I prefer the sound of the later SIDs after hearing them next to each other anyway.
I have a defective SID around here that is good for testing (filters are gone but it makes sound) if anyone wants it.