You might want to rethink using any rings with your new Hennessy. These can damage the suspension ropes and void your warranty. I would use the stock suspension as it is for at least the first year, which is the warranty period. If I really wanted to change the suspension after that, I might go to Whoopie slings.
Stock suspension lines on the Deluxe are a different material and much thicker than the ones one the Ultralight model, so the ring/buckle system that you planned to use might not hold the thinner rope, hence the recommendation against use with the UL.
If, in spite of this information, you wish to use the buckles, you may need to back up the rings with something like a Marlin spike/hitch to keep the ropes from slipping. With no experience here, I can't really advise you.
Hennessy Hammock afficionado and supporter.