During a glassy water takeoff and climb, best angle of climb speed (VX) provides

During a glassy water takeoff (ASES), after taxiing on the step, applying full power, and accelerating, what is the appropriate action to initiate the climb?

During a glassy water takeoff in your seaplane, rotate near VX of 60 knots, then accelerate in ground effect to VY of 70 knots before initiating the climb. If acceleration in ground effect is 2.5 knots per second, how many seconds should you spend in ground effect to reach VY?

After becoming airborne during a glassy water takeoff in an amphibious airplane, you clear a line of 35-foot trees along the shoreline located 800 feet from your liftoff point. With no further obstacles immediately ahead, what is the most appropriate airspeed to maintain next to efficiently reach traffic pattern altitude?