Rolan; regarding the minifish bailer; why about using a router and a spiral-cut (AKA "zip") bit to get a slit cut in the collar? Might need to lay down some py to add support but you'd have precise depth control and a narrow cut without damaging the fiberglass. A Dremel can also be used like this; there are add-on attachments that create a cone-like platform to keep the Dremel vertically aligned by hand.
