In the early 1990's I brewed several batches in 5 gallon (what looked like) pickle buckets. Just used the time recommendations. Never had any problems like Tom described, and mostly if not always the yeast was dried. Various British kits, all cheating with sugar IIRC. One was a Barley Wine, and it ended up definitely well north of 8% by hydrometer and human judgement.
I used plastic bottles with screw lids which greatly helped.
Basically I believed everything a local home-brew store told me. "Use this pink stuff for sterilization". Didn't ever seem to see either contamination or fermentation problems (might happen with insufficiently rinsed equipment?).
Once I tried using two kits of malt instead of any sugar. That resulted in a very mild mild. (Oh yeah, at one point I ended up with more kits than I really wanted because my father gave me some of his malt inventory after his diabetes set in).
Lets see. The spare hydrometer does sound like a good idea. And I believe I did crack a carboy once (before putting beer in it), but I don't really recall how.
P.S. Many commercial craft-brew stouts call themselves "Imperial Stout", and this seems to mean almost no head.