After posting the above info on my Facebook page, a friend who knows a thing or two suggested I try using Bar's Leak... couldn't hurt to try, might save me a ton of aggravation and money.

I bought the 24 oz. can of Bar's Leak Head Gasket Fix on my way home from the dealership. I put it into the cooling system per the instructions, and let it set up overnight. This morning, I had a flawless cold start, however I noticed that my heater core didn't get hot for the first 10 minutes of driving (well after the engine temp was up to normal). Eventually it did start heating up, after which I noticed the idle was not quite as smooth.

I don't intend to claim complete victory, because I know this is (at best) a stop-gap measure until the head gasket can be replaced. My friend said he was able to get a couple years' operation after using it, so I'm hoping it keeps me on the road for another year until I can sell it. thought I'd share the results here since someone else may also find it useful to try.

 

Just to close out this thread... the Bar's Leak has completely eliminated the misfires. The residual effect of the head gasket leak was that I get exhaust gas into the cooling water, but that is covered in a different thread.