don't bother with FHC on Island - the holder of will originals + films is Manx Museum Library (open Mon-Say 10am to 5pm)
Not sure where Gilmour trees are (? IoM Fam Hist Soc who have a library in Peel (Tue, Weds + Sat afternoons) but check with their website www.iomfhs.im)

Wasn't there much discussion re Gilmour (many spellings) on this board in past