I did most of my training in the type, and have only good to report. Although for travelling I would recommend something faster, perhaps a Remos or a CT. The Remos is rarely found second hand, which indicates to me that people who have them will keep them.
I cannot see anything wrong with an enclosed 912. Of the (more than) 50000 built, I'll bet you that at least 60% are enclosed, perhaps even 80%. I fly this config myself, in an Apollo Fox, and my one issue is that I cannot get the engine oil up to a decent temperature; I plan on installing a thermostat during winter.
As for the second throttle I'm afraid I have no recommendation. My own Apollo Fox had it, and I removed it. The construction is with a tumbling bar behind the dashboard, controlled from both throttles, and from which the two cables run to the carburettors.
Last edited by Jan Olieslagers; 5th Sep 2020 at 18:41.