Is this enough filtration ?
5 or 6.5 it doesn't really matter. There isn't really 65 gallons of water in your tank either. If you want to bump up the flow on the 2215s you can swap out the impellers for 2217 impellers. Also, don't run filter floss or foam in your eheims, it just clogs up super fast and slows them down. I just run coarse media in mine, you can let them run for a very long time this way.
We have a LFS here and he has an ADA 120-P (same as mine) 65G and he only has one 2217 on it and it is well stocked and looks great. I don't get all this filtration stuff, some people say you need 10x and other say you need less than 5x. Anyways, once I get it all set up I'm sure it will be decided.Thanks for your help, any other opinions appreciated also.