I would recommend putting a rail on the right side of the stock that way you can activate it with yoir trigger finger thats how i have and it works great you should give it a try otherwise good job!!
^^^ Nice! I have a Hatsan Gladius with 3 rails up front: Bottom and both sides.. That design was such a good idea that I ordered a few small rails to mount the same way on my PB. That's just the perfect spot for different accessories!