Don.
Your suggestion as to the exhaust blowing sequence seems to be correct. You are not able to hear the exhaust escaping through the Kingstons, quite often the people on the bridge reported when they observed the gas bubbles, but as everything else in the word, experience counts, an experienced engineer was able to tell when the tanks were fully blown by using his feelings. Normally you are not able to empty the ballasttanks 100%, you shall always have some residue ballast water left, however I never experienced any free surface effect from the ballast residue. I guess you guys making games for a conventional submarine with WW2 technique have your difficultes. The recorded WW2 parameters were scares and you had no computer to feed, old fashion experience, smell, temperatures and sound were important elements. I could be sleeping in my bunk when a change in the diesel sound woke me up and I was in the engine room before any messenger woke me up. Many things happened due to mishandling by unexperienced crew during the latter part of WW2 as the war had taken its toll and shortage of experience became a problem. If you look at the various intricate systems like the HP blowing system, engineers have developed same over the years and made modifications to be able to handle various situations. It took time and experience to handle all these options effectively which computers can do today, I guess it is possible to incorporate some of the elements by f.i transferring pressures into volumes in case of ballast blowing etc. to make the monitoring a bit more computer friendly but the real thing during WW2 was monitoring based on pressuregauges and time, the rest human senses and experience.
Tore