I'd also suggest buying in smaller quantities if you're planning on buying that much bitcoin; alternatively it might just be a good idea to buy coins off an exchange if possible so you're not exposed to the risk of being robbed or something of the sort buying coins IRL. I don't see news or articles about people being robbed in Bitcoin transactions very often, but that risk is always present.

 Might also be good to check the feedback or reviews that the buy has if applicable to get an idea of whether or not the guy you're trying to buy from is legit. One confirmation's just fine most of the time.