Yup... I started out with a machine that allowed about 10~15 minutes of operation IF taking it really easy, with a rather hands-on firing up and shutting down procedure, and turned it into a 50 minute boat (under practical conditions, with a lot of manouvering... At constant higher speeds it still is only 35 minutes, but nobody does that...) with a starting up and shutting down procedure that takes very little attention.

50 minute non-stop runs without any manual interference, removal of slops or refills of water are routine now

Took a lot of R&D to get there though. But THAT is the fun in it...

The engine now has about 38 runhours on it (which, if I check around with fellow model steam operators, is an awful lot in a very short time) and runs incredibly smooth now, I guess it has gotten broken in properly in the meantime.
And the good thing is: I see zero signs of wear, slop, play or deterioration of performance. Especially that, was something nobody including me expected, given its Chinese origins.

I also learned a good bit about the effects of water quality on the behaviour of the system. The investment in a water destiller and a decent conductivity meter, and doing regular checks is really worth it, the system will perform significantly better.