Lufthansa confirmed that that they will have no problem operating without the stab fuel until the solution is found.
They are confident the aircraft will have a 8000nm range with a economical payload and should gain 300-400nm when they get the stab fuel.
Longest route they use their 744 on currently (and longest route in the network) is FRA-EZE.
Keep in mind that unlike CX, LH operates the 744 at 394t MTOW vs. CX's 396t (on some tails).
Their second batch of deliveries only have a 385t MTOW and don't even have the stab fuel tank. (still manage to operate FRA-EZE).
Regarding the 748... boeing just announced a 6t MTOW increase via service bulletin. Aircraft already in service with 442t will thus go to 448t.