1. If you want to get them hemmed, wash them first: even if they are sanforized, they will lose some length. The "wear for six months before you wash them" rule is if you want to have the most visible fades. If that's what you want, you can flip up the cuff instead of having them hemmed. It's a fashion that some like, especially when the underside is very spectacular (thinking about the hand-dyed weft N&F just released), though you can also flip them to the inside of the jean if you don't like the look. For my part, since I want them hemmed and I don't like the flipped up cuff look, I treat them as any other pants: I wash them and I get them hemmed before I wear them.
Remember, they are your pants: wear them the way you prefer.
2. As mentioned previously, is that 32 waist in other jeans or your actual measurements? I have a 38'' waist (measured with a tape) and I wear 36 in Slim Guys. Check blueowl.us or tateandyoko.com for the actual measures.