I've had good luck with both Damon Rinard's spreadsheet, and the calculator on DT Swiss's site. I'd suggest you get a second opinion on the preferred dimensions.
I had some problems when I screwed up the hub flange dimensions, and wound up off by 4 / 5 mm. But if you got those right, and you're really after 296 & 297, I would have bet money that you'd be OK with all 297.
Then again, I don't win all my bets.