Hello guys.. today i received a nd4 filter from ebay for my gopro 3+ on my dji phantom 2 .. i have one issue, is it okay to use the gimbal like this ? the weight of the filter is heavy enough to make my gimbal lose the balance .. what should i do ? thank you

I have seen where others have balanced the camera by adding a coin or similar item to the rear with double sided tape.  Do a forum or internet search, and you should find additional info.