Really appreciate all the help!
It sounds to me like the way to go is to eliminate the head fittings by glassing, and to remove, expand, and properly fit a new drainage system, and I will make sure to get good ball-valves or seacocks.
I am mostly sailing in the Columbia River, and there is no chance that I could legal pump overboard, and I have very little interest in setting up a holding tank system. My original idea was just to glass over, but someone had talked me out of it--sounds like my original idea is the winner.
One more question: that mess of fiberglass around the inside of the head--does that entire area need to be cut out and re-glassed? I can't tell if that was a previous repair (possibly a poorly executed one) or if it is a sort of fiberglass backer to flatten out that area. To me it kind of looks like they actually just glassed in a pipe and there is nothing supporting it
Helen: I am trying to do this project on a tight schedule, and I am posting daily updates to my twitter account @harraik if you want to follow along. I will definitely post an update here when it is all done as well.
I need to go invest in a grinder. Any favorite models for this type of work?
Really appreciate all the help!
Very helpful links Mitiempio--hopefully that article and my copy of Don Casey's sailboat maintanence manual will get me through the process.