I don't see the value of the 'towering' takeoff. This seems to be a Brit thing, & I've never seen it used in the U.S. It takes less power, IMO, to do a moving takeoff, keeping the pitch attitude constant throughout, than it does to try to go straight up, to a zero rate of climb, or close, then try to transition to forward flight. You'll likely lose some altitude, & end up closer to the obstacles. The only time either of these is of any use is when there are obstacles to clear, anyway.
When you fly UH1's when it's very hot, high, & humid, you soon develop a technique that works for getting out of an LZ, & I've never seen a huey driver, current or former, use the 'towering' technique, & I've been around a lot of huey drivers over the decades. We just put the nose on the top of the trees and keep it there until the trees go underneath it.