We do this as a sim exercise for a double fail after T/O, to simulate losing them entering a CB/rain at about 3000 feet. We've got Vref +80 on the clock when both fail. I used 235kts as it equated to best ANGLE of climb (best angle of non-descent?) Inflight start on eicas says 240 for a relight using the fuel control off-then-on method to reset the starter logic for a quicker relight.
Guess I just hate not getting a definative answer.
Thanks for the input, guys!