I think I found out why there are so few "ultra fine" grips to be found. I got one, then a seat with a hood to be inserted into the grip, and there is only 1/4 inch difference between their diameters. Is the flare on the other type grips there to accept the hooded reel seat? Will a ring type seat work with this ultra fine grip? And if so, is there a maximum weight rod that you should use a ring type seat with? This is a 5 wt I have in mind.

Most straight rear taper cigar or superfine grips do not work well with seats that need the front hood inletted into the grip. Most do better with a downlocking seat that just fits flush up against the back of the grip. Usually you would put a trim ring there. These are usually supplied with most downlocking sliding ring reel seats.

Karen , like Bill said , most are too big for that grip . REC makes a few ring and seat sets with hidden hoods that are about .625 of an in. I think that they would be too small for a 5wt though . You can add a couple of rings to the bottom of the grip and shape to a flair on the bottom , then bore a recessed hole to accomidate the hood you intend to use . I have done this with preformed grips with good results in the past , but a lathe helps alot. Have fun , John