KIFIS--- Height or Speed... wouldnt it really depend on what stage of the flight you are.. in a b737 if i lost both engines at cruise id maintain height till i got down to my best L/D speed ( pretty much the same if i lost one engine only ) before i started to descend.... basically converting EXCESS speed into height.
At toff ud follow your toff segments to meet obstacle clearance climb gradients( a min req of 2.4% on b737 in the second segment.... where ud probably be maintaining toff flaps, toff thrust, gear up, and speed of v2 to v2 + 20). the third segment ud be cleaning up ... and the height would basically depend on the obsatcles in your toff path and being able to clean up and set MCT on your operating engine within the toff thrust time limit of your engine.
so u pretty much got it... u need the speed but only so much ( best L/D ).... after which anymore is only a DRAG.