You can not lower that elevator linkage. You set that so that the horizontal part is 90 degrees to the vertical arm (there should be a window in the side frames to see the horizontal arm so you set it so it is centered in that window). You then set the other two servo-swash links as needed to get the swash level. IT doesn't matter if the blades are 0 pitch at this point, what you want is a blade showing the same exact pitch reading around the full rotation of the rotor sweep. This will mean that your swash is level. Normally, however, you do not set swash level with this method, you either use a swash leveling tool or the old zip tie trick.
Once the swash is level and the servo horns are 90 degrees, you put the rest of the head assembly on the main shaft and then 0 the blades using the swash-bladegrip links.
If you intend to use the blade pitch as your measurement of swash level make sure you are using a manual dial pitch guage. Digital guages don't work well for that kind of measurement since zero reference is different at each point in the rotor sweep. Dial guages reference against a bar on the rotor hub or some other fixed reference (relative to the blade) so they work much better for that purpose.