I had one connection that seeped a bit when I first tried. It stopped when I retightened it (I loosened and then retightened). The difference was that I used copper-nickel lines versus your stainless steel lines, which are harder. You might try loosening each one then retightening and see if that fixes it. The brass should deform enough to make a good seal.
But you do need to run out and buy a full set of Snap-On tools.
(No don't do that unless you're using offshore tools. Mine are either Craftsman or NAPA and fit fine.)
