Hi Craig, I don't think I can shed any more light on the 'miscellaneous' wills either. Joyce makes no significant mention of them in her introductory notes, and the ones I am putting up currently (1600-30) seem rather few in number.
Michael Bridson contributed a few wills of this period to Brian Lawson, and appears to have transcribed them at the Manx Museum, These may be on a film Joyce has not looked at yet. Some wills are not in chronological order, so the one you are seeking may be buried further on in the series of films.