It Isn't too much, no. we generally recommend 1Tsp/gallon on this forum.
Remove the plants if they bother him. If you can, buffer the light that reaches his tank, try putting a sheet of paper over the lid, etc. bright light is stressful.
If your big tank is large enough, why not just float that container in it? Leave the lights off on it and cover it so the two fish wont see eachother.
Aquarium salt can burn him if you don't dilute it in another container (like a gallon milk jug, two water changes a jug for you!). You just put the salt dose in the jug, shake it very very well, maybe let it sit for a minute, then use it. :)
Congrats on him Im rooting for the boy! More pics would be nice :p and I usually add 1/2 tsp per gal to see if it will help and then up it 1tsp per gal if its not helping. I dont like to over compinsate if I dont have to I just try to get just the right amount.