The problem with that StahnAileron is you're just one bad engagement away from having your flagship undeployable.
That's only if I do that with ONE ship. I don't do that with one ship. I only do that when I have MULTIPLE ships. I always have enough crew to man my personal flagship. And my flagship is ALWAYS the first on on the fleet list, so it get crewing priority. The ships I don't want manned I always place at the end of my fleet list. My assistant ships would go in the middle, so they get crewed as second after my flagship. If I lose crew, they are the first to go unmanned, not my flagship.
Once I DO start overmanning my fleet, it usually means I'm using enough FP to do large scale engagements and can select my deployments. Still, I generally stick to about only 50-100 crew over skeleton requirements when I'm using larger vessels. With a fleet of smaller vessels (I tend to use Tri-Tach High-Tech ships), I only keep 5-10 over. Tri-Tach frigates have very minimal crewing requirements.