did you try putting a toothpick behind the side plate to be sure your not torqueing the bow, because if I torque when tuning my arrows kick left ? Im sure you know you should be going nock right for stiff out of a RH bow all day long,,, Id say try 2" long 2016's with 125's or 1/2 to 1" longer 2018's with 200grs up front if its heavy R/D bow..
as far as FOC if you're bareshafts are flying straight and your POI is on wait till the summer to find a good FOC,, unless your not hunting now I wouldn't sweat the FOC for deer size game or smaller right now those arrows will be marking the first splatter I guarantee it....