RE: Attaching battery to engine mount
I had the same set up with a Sig Cap ARF and a Saito 180. Needed about the same amount of nose weight.
Do not mount your battery to the engine mount. Its not that the mount would suffer, but your battery could have a problem. That Saito 180 is a shaker. Batteries hate this. I mounted my battery up against the fire wall and added weight to the motor mount with some epoxy glue.
Tonyc