I think it could be productive to co-ordinate with what the Civil Registry decides to do. Each time I speak to Sue Cain she is positive about the probability of indexing proceeding, and maybe the growing availability of UK civil registration material online will encourage the authorities over here.
The IOMFHS remains a potent force inasmuch as it has financial resources, a legal personality, a track record of achievement on which much of the current online data rests, and is ready to spark into life if the right personalities become involved.
I have felt for a long time that the most difficult period for Manx Genealogy is the period 1790 to 1840, when the clergy became Anglicised and the population exploded. While the same christian names were used, there were few second christian names, maiden names fell out of use, nick-names ceased to be applied in the registers & so forth. Also the manorial records ground to a halt, with only a fragmentary Lib. Assed. between 1797 and 1858. My feeling is this is the most useful period to start with.
Also there is an amazing amount of untouched data in, for example Chancery Records as well as Lib. Vast, whereas with PR indexing to some extent we are fishing in the same grounds as before, although the illegitimacy issue is very important, also the "Ballafreer" type of entries in the IGI.