I just did it with Sierra Nevada pale ale. I poured 3 bottles into glasses. Sanitized 3 pieces of foil, covered them and while I was waiting for them to come to room temperatures made a starter with a low gravity (1.010). I swirled the bottles and poured them in to a 40ml starter and covered...
I would definitely have 05 on standby. I would personally go ahead and pitch it. I ruined a batch with diacetyl once due to a long lag time, but that was because I drank to much and forgot to aerate
It took about 12 AG batches and pretty much every improvement you could make, temp control, oxygenator, stir plate with starter before I made a beer that I deemed drinkable. I think a kegging system and using acidulated malt to lower ph ultimately is what made the difference