The raw and one wash are the same thing for all essential purposes. Once you soak your jeans and waste a good bit of time with the soaking, you'll realize that you have pretty much the same thing as the one wash. I would recommend going for the one/wash because for somebody who is new to this like you, its much easier than to predict shrinkage and how they will fit for the raw. I purchased the raw version of these jeans, but simply for novelty purposes and because they didn't have my size in the o/w. You definitely want to hem these jeans. They are not the quintessential slim jean and are based off of a vintage (67') cut. Having that much stacking and having very slim just accentuates the fact that they are very roomy in the top block, and decently slim. They're not that small in the hem, so lots of stacking makes them look sloppy. Technique has a great fit on these, not the average 811 fit, but still nice. But, they do look sloppy because of the length, and a hem would look much better. What I would do is hem to +2 of your true inseam to account for any further possible shrinkage and to have a bit of stacking. Besides that, they're a great jean, you'll really see the difference between them and what you were wearing before.
Sir this is by far the most informative post I've seen so far,Thank you!