There is no weight limit to flying by chopper however in saying that if your to large to fit through any of the emergency exits on the chopper then yes you wont be allowed onboard . As I am sure you are aware all people going by choppers these days have there Shoulder Measurements taken please go to this URL https://training.aisgroup.co.uk/course-details/172/shoulder-measurements
I think the cost is about £28 . I am over 6ft 3 and my weight is 128 Kg and they just just me next to the door and never had any problems .