I have changed all the oils and run the outboard happily from both its internal tank and the external. The water tell-tail is spewing nicely, so I don't think I need more of service than that for this year. A full professional service costs about 25% of the cost of a new engine, which seems way over the top, so I only have it done every few years. Hope I don't live to regret it.
The motor well blanking plate fits in under the engine much more easily now that I have removed the projections. I'm much more likely to use it now. The raised floor boards can only be used fully if the engine is tilted down into the water. If I want it tilted up, I can only raise the forward half of the floorboards, which is what I expected. The outboard really is quite obtrusive into the cockpit.