Apologies for the snark, but if my goal was to maximize expected return, I think I'd probably not do a startup at all and get a nice salaried job with a government contractor. Startups are risky! And it's hard enough for me to judge the risk/reward of my own startup, let alone someone else's.

If I wanted to take out some risk, I'd rather cash out some equity using more traditional means and putting it some place safe (or at least different), not other startups.