Centaurus, I would be interested to hear your views on the procedure of leaving the undercarriage retraction until the aircraft has reached blue line.
When I did my initial multi-engine rating I was taught to use the blue line as a go/no go speed. Engine failure before then, close the throttles and either stop on the runway or land on what runway remained even if that meant going through a fence or overrun the runway. Engine failure after blue line then Phase 1 actions etc.
The rationale was that the aircraft was unlikely to accelerate to blue line with an engine out so it was better to put it down in a controlled manner than to lose control at VMCA or such by trying to make it fly. By leaving the undercarriage down it made the job of putting the thing back on the ground that much easier.