Like I said before, my recon fighters rarely if ever have a sensor. If you have an active grav sensor, it has a passive receiving array. Which means, anything that has an active, and is within range to detect another ship, chances are, they detected you by your emissions, and will blow your smeg up. However, if it's early in the game and my resources are limited, I do put resolution 1 sensors on them, and thermal arrays, but I only turn those on, if I detect missiles coming at me, by their thermal emissions. But this is dangerous, and you need great thermal sensors to detect missiles before it's too late, plus you lose out on that initial bonus. Eventually I just figured, it's not worth it placing even anti missile sensors on fighters. But that is something you can only deal with once you have sufficient experience in situations like those.
For newbies, I would always recommend a sensor on the mothership that can cover the entire bingo operational range of your fighters (45% of your their range), and anti missile sensors on your fighters only IF you use gauss guns or railguns. Don't even bother if all you have is a single mason. You will not defeat missile waves with those.
Also, I never bother with missile fighters. Releasing one or two missiles is completely worthless compared to the space that needs to be dedicated to the carrier for the missile magazines to reload the fighters, the hangar deck, and any supply ships. I only use energy/projectile weapons on my fighters. It is better to dedicate that space and escort to PD.
As for larger sensors, once again, it is unnecessary. Your friendly capital-ship sensors should detect enemies, not your fighters. Any sensor you can put on a fighter is not really going to cut it for your operational requirements, unless they are for self defense, or detecting active emissions. Remember, the USAF Raptor is a stealth fighter as long as it doesn't turn on it's own radar.