Thanks. The drawdown is not ready for prime time indeed, I haven't traded it for that (among other) reasons. But I like the idea a lot and the futures linked ETFs seemed like an easier place to start that the contracts themselves.
Futures linked ETFs in general are a great approach that have really helped "retail" traders get access to a previously difficult market.
Ernest Chan provides some good examples re GLD/GDX spreads, for instance.