I agree with Mach E Avelli, I'd never dump flaps. Having had 4 engine failures, 2 of which have been on take off, it is a recipe for disaster.
My first twin was a L12A and the last thing you would want to do is dump the Fowler flaps.
Every endorsement I've ever done has been identify, feather, gear up and control. But most of all CONTROL.
Better to have a prang at the end of the runway with wings level than cartwheeling because you let the wing drop.
As for decision height, I can testify. ALL non transport category twins have a decision height of around 400 feet.
Picture this scenario, Pa39, 8inches of left prop broken, engine feathered but canted 10 degrees off centre, night landing. This is what I faced in 1984, flew the aircraft 10 knots above approach speed and made the decision height 500 feet. Result here to tell the tale.
If I was to repeat my career And needed to do an initial twin, I'd seek out an older instructor with experience. People such as Bill Whitworth at Bankstown or his equivalent in Moorabbin or Archerfield would be money well spent