an alternate way to see it is that you need good rest. hab in at least 1 engy...
remember that Reps and Engys give SD, but Engys also gave Rep, while rep dont give u Engy stat.
so if you are going for 5 engy 3 rep config you need to lisen to the guy just posted above, but if you are going for a 4/4 config (most common in any nation) then rep. hability its not so critical, due to the fact that your reps are going to reach the cap (well BVE of course).
There is when rest. hab comes into play...
its very common to use engys not only for BB, you will use Engys in PCV, SS and even in low ships while lvling other sailors, so having a good SD stat will give you extra life in times when you cant repair fast enough and your ship have low life point.
So getting at least 1 Engy with stats like these: 12 eng. 11 rest. 10 rep its your best choise, considering that you are for shure going to need this hab.
for most SS you also need good rest. hab for your engys, due to the fact that in a SS3 you can run only 1 engy