Just to follow up: AMD kept rallying today, so I spent the last few hours tracking the premium and watching the greeks, then closed the trade when it peaked for a $77 profit. Interestingly, even though I expected the premium to start rolling off below the sold strike (85), the roll-off point came well before I expected it - around 82.75 rather than the 83.50-84 range that the analyzer showed.
Overall, I'm pretty happy with what I got out of this experience: some refinements to my defensive strategy for short puts that go against me (don't roll out the put once you've sold a call, because you end up exposing yourself to more upside risk), and a reinforced sense of doing the right thing for buying a cheap call as insurance. I still wish someone with more experience would add a bit more perspective - perhaps suggestions for other defensive strategies and their pros and cons, or things I could have done better with this one - but hey, it's all good.
Thanks to everyone who offered useful suggestions and food for thought!
Your max profit would've been if you closed both the call and put when the stock is at the strike, since that's where total position delta = 0 and that's where your straddle forms its peak
