That would probably be of interest to quite a few of us. Although my boat already has a D5 fitted, the installation does not look very professional and I can foresee some re-work being required. The heater was installed about 4 years ago and I am already having to re-attach the exhaust pipe as it has corroded for about 3″ and disintegrated where it joins the heater body outlet.
Also, the installer claimed that to get sufficient air into the neater he had to cut a large hole below the cockpit transom seat, opposite the gas locker. I was dubious, but it did seem to fix the “cutting out” problem after installation. I am thinking of moving the inlet to inside the boat, maybe stern cabin rear bulkhead, as this has been recommended on this forum before. Where did you fit the inlet in your boat?
One reason for thinking about moving the inlet is that I found that hot air was not reaching the forward cabin. I had to diconnect that outlet and reduce the outlets to saloon and stern cabin. Maybe taking in warmer air will help that.
Maybe your installation guide could be a magazine article. Jacqui is always on the lookout for such things.