The problem with the Dowty, Buehler and Hamilton, they were all franchised by Hamilton to each country, so in each country they did what they wanted, whether it was cost, quality or design. None of the designs for installation are what I call good for a boat that was originally built to be a water bourne Land Rover or Jeep as they are so difficult to repair. Concept excellent, fun brilliant, reliability dubious, repair very difficult, that is why there are so few left.
Dowty of course are the suppliers of most aircraft landing gear, so how they became involved, who knows. Dowty then sold the boat side to Boulton Paul in the UK, a contract house and factory building company?
Re the inspection mould on the top of my housing, the earliest did have a glass access, but they frequently smashed with stones, so that was stopped. This lead to the more difficult shimming which I still have difficulty with as no one has any data or how to do it easily.
Re the re-homing of your unit, perhaps you could mould them in like mine using an alloy base plate. I had mine professionally moulded, but in hindsight, I could have used a chunk of alloy and hand cut it. but it would have had to be 1 inch thick, so I chose casting. Re the studs or bolts, they will last a few years, but with regular service, and brass nuts, they may survive a little better. The two studs on the back of my housing are a night-mare to remove the nuts from, unless the rear units are removed first as they are hidden.
The reverse bucket was a great improvement on the 'shutter' which is useless. I was used to no reverse with my direct drive, no reverse and no neutral Albatross, so did not concern me.
Lining up the impellers is a true nightmare; and that does not include the thrust shims. I have no idea how other than by trial and error, which involves setting up, measure, remove, make shim, re-install etc etc.
I am struggling now due to old age a heart condition and few skilled engineers in this country now. I have a toolmaker, fabricator and a foundry, but nothing else and I am lucky. All the best BN