I think this is in the mechanics forum. But it might have been lost...
Smaller objects require a tighter (smaller) resolution. For missiles, your best bet is resolution 0 (or 0 tons). For Main fire control, I usually go with a 1000-2000 ton resolution and increase the antenna size for the desired range. For search radar, I go around 5000 ton and the antenna size for the range.
Advantages of higher resolution (and by higher, I mean a smaller number), you can track smaller objects easier.
Disadvantage is that your range is more limited, you need larger antennas for the same range as a lower resolution suite.
For lower resolutions, reverse the ads/disads.