I pretty much only use the Robart hinges and the above tool really helps. It is best to drill your hinge holes before you bevel the hinge line. This way the jig works better to ensure you are drilling exactly on the hinge line.

As for the stiffness. Sometimes, the hinges will be a bit stiff out of the package. They will loosen up. It is also possible that one or more hinges are not perfectly aligned. One could be in a different hinge plane (fore/aft or up/dn a little) or twisted/rotated slightly. It doesn't take much error... even 1mm is enough to make the surface feel stiffer. If the control surface is not perfectly true (warped/slanted), this can put pressure on some hinges making them bind a little. It is also very easy to get a dab of glue in the hinge or next to the hing or in the hinge line that will cause surface movement to be a bit stiff. If the surface moves without jerking or catching, and is just stiff, I'd say you are probably fine. You can try to work a little Vaseline into the joints if it really bothers you, that should help.