Despite such claims from a few people, I've yet to see any proof that any planets' signal ranges overlap. But if you do have any proof, please do share it, it would be good to know.
As for not knowing for sure, and needing "superman eyesight": that's a first I heard. Say, what's your resolution, your screen size, and what distance do you sit from it? Have you had your eyesight (visual acuity) measured? (I've known people who thought they had good sight, but after they went to a doctor where it was actually measured, it turned out that they needed glasses.) You might need to adjust where you sit to see better.
Eh. There's no overlap. Once you center your tuning dial on a signal it is definitive what the body is. As I said before, determining exactly what a body is in either takes a small amount of time and 'extra effort'.
Honestly, I play in VR, supposedly the worst way to use the FSS, and I had no problems.
Edit - And for me at least, determining if traditionally valuable bodies (ELW, AW, WW) were present was pretty easy as their location on the spectrum is pretty obvious, and usually totally empty.