Neither the 47 or the 55s will give you cut a la Helmut Lang, to be honest. You'll only be disappointed, especially with the seat being cut two fit two Helmut Lang asses inside of them. Check out these.
They will be much more along the lines you're looking for. They are unwashed with redline selvage like the repros, but the rise is lower, the seat has a much closer fit and they are a slim leg (slightly tapered). They are also sanforized, so if you do not want to wash them right away, you don't have to worry about compensating for shrinkage. Sizing is true to tag, and they come in one length (34"). The Anglaise cut is looser (not baggy, more classic), but has the same rules as far as length, selvage and denim quality. If you're really bent on getting Levis repros, the 1947s are the slimmest. However, the rise is high (think 12", instead of 9" like HL). I am not a 501 man myself. I admire the Levis heritage and the importance of the 501, but they just don't look good on me, and it sounds like you're into the same cut that I am. If you want a nice, regular fit straight leg jean with unwashed selvage denim, check out Uniqlo, as I linked earlier in this thread. So cheap, and a more updated cut than the LVC 501 repros. I think 30 pounds for their selvage jean (available in England, though I'm not sure where), and they're really sweet; take my word for that. There is also Nudie's Slim Jim (straight) and Super Slim Kim (tapered), and Boot Cut Ola (slight boot). All of those have a nice slim leg.