The correct way is the tip of the tongue to the tip of the reed. Art of Saxophone playing is very good on this with lots of pictures and diagrams, though it does get a bit "wordy" at times. The other method you mention Linky is good for double tongueing, but I would avoid using it as a primary mode of articulation, especially when you get to fast passages that aren't quite fast enough to double tongue.
If you find your articulation is too heavy, I have an exercise I use with my students with the same problem. I have them tongue the corner (shoulder) of the reed with their tongue. The goal is to get a "false fingering" effect. Think of the sound a horn would make if it could speak toodle-oodle-oodle repetitively and quicklyThe articulation doesn't completely stop the vibration of the reed, but merely hinders it a bit. If the articulation is too heavy then the sound will stop. This doesn't correct the problem itself, but does give the player a self-assessment, and helps solidify correct tongue placement and dexterity of the tongue.
(It's also a damn cool jazz/blues effect!)