As stated on the WOA, the shoulder angle and neck diameter are different. Since they are a wildcat, I'd go with the WOA or the PDK and get the most from the case in an AR. Pretty much a neck up and shoot, no need for any case-forming gymnastics. The first firing will shoot fine. I have an AR match rifle in 6PDK which takes the 6.8 case, blows out the body, improves the shoulder and moves the shoulder forward about .050" so it has a couple grains more capacity and just a little more work to form. I fireform in competition and they will clean the x-ring if I can. I just finished loading some moly coated Hornady 87gr HPBT for a match tomorrow with 28gr of Varget in SSA cases. It is a mild load. I'd advise staying away from SSA cases, mine vary a lot in neck thickness and I've never heard anyone that knows what they are doing say they are a quality 6.8SPC case. Hornady and Remington get good reviews but watch primer size because some use LR and some SR and capacity is different. I've got three or four firings on my SSA and I continue to get neck/shoulder splits even though I annealed twice. I'm going to Hornady when I get tired of screwing around with these cases.
Lots of 6WOA data on a couple of the Highpower forums if you search. This link has some data. RL15 is pretty close to Varget.
http://forum.accurateshooter.com/threads/6-woa.3745744/