<<I need one last project to do with my 8th graders. I love the Illuminated hands--do you think it can be done in 4 days (43 minute periods, good kids)?>>
Oh, I'd think so--even if you have them do the "light scales" first to get a feel for it.
I can't remember how long it took my (older) students to do these, but not too terribly long (their mandalas took longer). Of course this was during a special class that met for 4 hrs per day for 2 weeks. At first I was scared silly about having kids (very small group) for that long, but I loved it and so did they. But I think you'd be fine with the time that you have available.
And again, I really recommend Judith Cornell's book :-)