One thing to consider on a tandem is if the amas are too far back, they may potentially not provide the same stability as when mounted more towards the middle. Another thought to consider is if you will be fishing solo or with a partner on your kayak.
I have a revo 16 and I mounted mine up front. There were a few reasons for this. 1. It provided the most ideal stability for sailing and 2. I was able to easily through mount the hardware, where behind the seat wasn't an option. Now I only use the amas when sailing.
Here is a video of them in action on my boat. But I haven't had any issues fighting fish.
I would suggest dry positioning (don't permanently mount) the amas on the kayak. Sit in the boat and practice casting or extending the rod as if you were fishing, reaching forward over the bow and see whats comfortable and best for you. Also consider accessibly and the needed footprint for the amas and hardware.
Cheers!
I