Great to hear that you're rebuilding the DV20, and would like to hear how that goes. Mine had a new head gasket 3 years ago, and has the mechanical fuel pump removed, using just an electric one between the tank and the injector pump. No problem with it, except it always seems to take a couple of drops of my outboard gasoline (with 50:1 oil mixture) in the small hole in the air cleaner intake to aid starting if the engine has been sitting for more than a day or so. Otherwise it starts right away, and runs quite smoothly, powerfully. Do you have the manual for the engine? I do, & would be glad to help out with that.
Other documentation I have is the brochure that came with the boat. Its not really a user's guide (which I understand from other people on the YAHOO Soverel discussion group was never really developed), but it does talk about features of the boat, pics, specs, and drawings. I have these in digital form and can send them to you as jpegs or refer you to the YAHOO Soverel group, where I've posted them. Just let me know.
Good luck with the engine,
I also have a Soverel 30 Mark III. I'm rebuilding the the DV20 right now. I got a used head for it from England. I was hoping maybe you have some more documentation for the boat, that you would share with me. I don't know if my is suppose to be rigged cutter or not, and would just love to see what the user manual has in it if you have one.