TecPilot.... You make good and bad points. I don't have time to list all your errors right now but will get to them in time.
Firstly, an Mi 8 has 2 Hydraulic tanks, not one as you stated. The Primary and Secondary hydraulic systems are completely independent of each other except that they work through one set of servo actuators - unlike e.g. a Puma which has 2 sets.
Secondly, I have read every English translated Flight and Maintenance manual supplied by the factories and I challenge you to show me where your sentence "...For Gods sake don't pull the collective at more than 1 degree per second" is found.
Doesn't exist.
PS All your engine stats are quite easy to quote for anyone who can type "google".