Thanks for all these great tips. I have started building my 18' Merganser II, planning to glass the inside of the hull as well as out for the additional strength and water-proofing. However, without thinking it through I went ahead and taped the fillets instead of just laying the glass sheet over the inside. Oh well, a little extra weight but probably a whole lot more strength.
I did keep the fillets small though, and will use cab-o-sil to help lighten the end pours. I'm not planning to drill and put in lifting toggles though, so how small can I safely go on the end pours since I don't need six inches of depth just so I can drill them out for toggle placement?
By the way, I also taped off and pre-stained a pattern on the deck panels, that should look pretty cool once th eboat is done and hull painted.
Bruce