Hello Sue,
Good news that you will add to the transcripts. These have been kept going by Ian Radcliffe since Brian died. The webmaster of the IOMFHS site prefers to copy them across from Ian's website.
See: lawsonsiom.freevar.com/ for recent transcripts (not yet on the FHS site), as well as the "Main Wills Index" there. Ian's address for transcripts is: ijradcliffe(at)manx.net [(at) = @].
If you had given yourself more time it would have been better to photocopy the wills first through a Family History Centre to save precious time at the MM library, but it is certainly faster (and cheaper) to do research on the spot where the films are immediately freely available - except, in my out-of-date experience, photocopying in the MM was both painfully slow and expensive compared to FHCs. It might be an idea to take a digital camera in case they will allow taking photos of items like index cards and other documents.
By the way, those LDS film numbers on Brian's indexes, and the one I gave you, are not used in the MM although the films are the same. You choose the film by Court (Epis) and date (1861), and of course the will number is the same.
Sue