Originally Posted by twocicle

I'm not a fan of using pure RD tension to keep the chain from skipping on a big cog. The issue is really due to inadequate chain wrap from having the RD cranked back so far in order to keep the top jockey wheel from hitting the biggest cog. This can be seen in the video clip where the chain wrap ends in almost a vertical plane.

Another option I would suggest is to find a smaller top jockey wheel (ie: -1 tooth in size). This is a solution that I have used in our previous Shimano 10spd setup with a 11-34 M771 cassette. A smaller top jockey wheel allows the RD to be set a little more normally under the cassette (less "B-screw" in Shimano terms) instead of cranked back so far as to cause the chain to skip.

Here's one other idea... does the Athena triple have the same throw ratio as the Shimano XTR/M9000 RD or the one from SRAM? If so, maybe swap out the RD. The M9000 RD can handle up to a 40T cog and the SRAM up to 42t.