A RF of 7 Hz will only be a problem if there's some energy source near that frequency to provoke arm/cartridge misbehavior. I don't believe 7 Hz warps or footfalls are particularly common.
If you want to raise the RF slightly you could try some lower mass weights. Otherwise, if it sounds better with the weights than without, I'd say enjoy.
If you want to raise the RF slightly you could try some lower mass weights. Otherwise, if it sounds better with the weights than without, I'd say enjoy.