Best O-line abilities? SP vs NS vs Identifier vs Threat detector?

Would having secure protector on all of your o-line make a big difference? Right now I have Trent Williams and Madden as my tackles and both have 0ap SP. I have Nasty Streak in both my Guards for 0ap and identifier on my center for 0ap. I'm thinking about getting BB Grady at center and he gets 0ap Threat detector,Identifier or secure protector. Which of those would be best to use? Identifier is nice but isn't really needed considering you see the user as soon as the ball is snapped so I could live without that ability. Getting 5 secure protectors for a total of 0ap is very possible and I'm just wondering if that would be the way to go or get threat detector on my center for 0ap?

I would go for secure protector or threat detector. Personally, I run 0 ap secure protector as that is what I value most for my players. But threat detector is very powerful for those who know how to the information from it properly. 

If you want better blocking from your center I would go secure protector. But if you like how your c plays without secure protector, I would go threat detector.

I would like to add to the threat detector vote, but id also consider putting a post up on a player too. I like to establish the run to set up the pass. So if u want to run efficiently, post up may be good on the center. Maybe look for a double 0 ability guy.

Sp is the way