Theo,
I too have 3 Asian 7750 movements. The newest b1 from the 187 keeps excellent COSC time. The 2 older ones NOT (in my 196 and 212).
BUT they all have good power reserve of approx 2 days without wearing.
Although I tend to wind them every 2 days like i do on the manuals. Keep in mind that wearing it in your wrist doesnt mean winding if you are not being very energetic.
Sitting at work for 8 hours for example and doing pc work doesn't wind the watch. Therefore you must wind it for 50-60 turns every 2 days and i think you will not have a problem