I would go for least rate of descent until a landing spot is chosen, then go for best glide range if needed.
I would worry that flaps 40 would require excessive speed and rate of descent in order to leave enough energy for the deadstick flare. The greater the R/D, the more exacting the flare required.
The last half of flaps is typically more drag than lift, not what you really want until maybe in the flare.
GB