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With the KUL keyboard, the grooves on the back are for routing the cable -- it can exit the back of the case in one of three locations. The smaller switches are for making modifications to the board's layout.
Brown switches are where a lot of people start (including myself). I definitely would have been happy starting with a Model M as well. A QuickFire Ultimate would be an okay first board, although if you're considering getting a set of replacement keycaps at any point, the bottom row of the Ultimate is somewhat harder to find keycaps for. You'd need to find a set with a tsangan kit in order to replace the ctrl, windows, alt keys, as well as the spacebar. It would be easier and cheaper to find a custom set of keycaps for the Storm Trigger or Quickfire XT keyboards, if they're available where you are.