Related to the above, a more sustainable goal around annual Eddington (sort of) is something like aiming for an annual Eddington defined by: 120 minus AGE. i.e. yours,
@bluenotebob , would be 120-72=48. The major benefit of that is that it is conceivable that you can still do it at 80 years old, etc., whereas
@MadMalx ' s one would need 80 x 80km, which sounds quite improbable; certainly *very* challenging. (Obviously, you can pick a different number from 120, that seems to me to be a viable one (though maybe I'm being unduly optimistic!).