Well, discounting the freak hand that our LHO pulled on us in the actual original, as an abstract problem I think I would try to buy it in 5♦ first. I might compete to 6 if opps bid 5M or I might not, depending on my mood, how confidently they bid over me, etc. And yes, I'm fully aware I'm giving them more room to exchange information than a direct 6♦. But I think the chance of buying it in the cheaper 5♦x is worth the risk.