I use two 110+ overvetted USN Seaman on my CVs.

There is a difference, but I would not say it is massive. It helps though.

The question is, what else to put on your R-Slots? Gunners for HH/AA would be the
only other usefull solution and if you need those, the chances are high your team
will lose either way.

"I could really use some input on this. Am I wasting a slot with my high level seaman? "

Maybe, maybe not. If its not high level (over 100-110 bve) then yes. If it is high level
then its doing something, the effect is not that much however and to me it just dose not
warrant giving up a slot for it.

"While we're on the topic of CV supports, is putting in a Restorer still a good idea? "

Can you think of any other sailor that will get you to 900sd on its own? Though I usually
do not use a restorer, I would rather use that slot to level something. But when I am
using my CV6 that gets no exp anyway I carry my restorer.

While we're on the topic of CV supports, is putting in a Restorer still a good idea?

I could really use some input on this. Am I wasting a slot with my high level seaman?

Well yeah sure you might not ever have a problem, but does having a seaman make it any easier?

I've never used a seaman and I have never had a problem against anyone with my USN
fighters. My KM is a different story but those are still pretty low level so some T4
players give me trouble.

I did some tests with high lvl high vet seaman.
No difference, means, my fighters were not able to shoot more planes than without
the seaman. Done with 1 and 2 Seaman against the same opponent FPs.

Furthermore, in the past I had the impression that the seaman influences the
distance that my FPs were able to attack, but it큦 not more than an impression.

when I have full vet and experts?

YES. If you have fighters, I suggest getting a high level BVE (130 vets+) fighter stat
seaman. You will see that this helps GREATLY. T3s will have a much easier time downing
many T4 FPs.