I have recently been using the narc/missle combo with good affect. I believe the narcs only work with missles that have guidance or lock on capability. Most of the srm and mrm missles do not have lock, you aim and shoot. This means you need to lead the target with srm and mrms if they are moving.
The narc does work with arrows and LRMs. Have not tried them with the streak missles. The narcs IMHO will be most effective with LRMs and little less effective with arrows. arrows have a much flater trajectory and don't turn as neatly. I have seen an arrow pass the target and kind of loop around in a tight area before flying back at the target. But hits with arrows on narcs are not guaranteed unless you are aiming in the general direction of the narc to start with. But then when I fight I am usually close enough to just point and shoot the arrow into the target, no narc or lock on used.
The best combination however is if you can get someone to work with you. Urit and I did that and had very good results. I was in a longbow with lots of LRMs. He narced a target and when I heard the beep I started launching rack after rack of LRMs over the hill top I was hiding behind. Believe as a team we managed to get 7 or 8 kills and a good amount of points. Would be even more effective if there were two longbows launching at once on a single narced mech.
Hopefully will get to try this again.
Another thing I have found is that to hear the narc beacon I think you have to run passive. Not 100% sure of this but that seems to work better than if you are running active. But I don't think you want to run active anyway. If you are 800 meters back behind a ridge or hill from the enemy line and your narc support is also running passive the enemy team will have a difficult time figuring out where you are since the missle boat does not even see the target and in theory is not in range of the enemy radars since you are passive.
I need to fine tune the longbow for this role. I think a little less armor and more heat sinks and more missles are needed. Ran out of ammo at least once when Urit was narcing for me.
IMHO this tactic is one of two methods of using missles effectively. If you think you are going to use the normal missle lock forget it. Long range snipers will hammer you into a smoking wreak before you can launch more than 2 or 3 racks of missles. The lock takes way to long and you have to be exposed to get the lock. And since the missles have about the same range as the large lasers, PPCs, and gauss rifles a missle boat does not stand a chance.
The only other tactic of using missles is to get in close and narc your own target then fire the missles as you dodge and try to get to cover.
Of course you need to take this information with a grain of salt. I tend to leave large numbers of burning raven wreaks on any map I fight on.