Hi Doug,
As you probably know, film 106366 is the mainly hand-written index to Epis wills 1659-1949. This film, and the Arch index, were what Brian mainly used to compile his consolidated wills index. Before he published this on his website (now at www.iomfhs.im) we would look up the index on film where wills are listed by parish for each year to try to find ones for our families. Even though there are missing entries, and some years not covered in the indexes, it is interesting to see these films which often had added details (e.g. place names) not transcribed by Brian.
Few people would have ordered them after Brian started his website, because he made it so much quicker to find possible family wills, and to compare them with the burial dates also listed by Brian. But those original indexes are well worth looking at, so you won't have wasted your efforts. Because it is so many years since I (and probably others) last ordered that film, they probably returned it to Salt Lake City, and will need to get it back for you.
I'd look at the film compared to a print-out of the surname you are looking for from Brian's wills index, and a print-out of his burials, which will make it far easier to look through and to find your names, and because he has also listed the film numbers for each name you won't have to find these (although it wouldn't hurt to double-check).
Sue