Ok, I have put all the required structure and control system parts into CAD for analysis. The data I loaded is all directly from the most current set of plans I have. I have not compared it to the very old set I also have, but some of those drawings do have revisions in the current version.
Here is a overview of the drawing I made. For control neutral, I assumed a 5 degree forward cant of the control sticks, and that seems reasonable. I did not include any aileron control parts on the drawing, so that is why the control stick look funny. The square at F-605 represents the per-plans vertical dimensions of the pushrod cutout.
The fuchsia lines represent the control system with Max (25 Deg) down elevator deflection.
The area circled above is shown in more detail in this image. The green line is the top of the seat rib. The fuchsia lines are the pushrod width and centerline. You can see that the pushrod is breaking the plane of the seat pan/seat rib top.
Here is the system again with Max (30 deg) up elevator. This is based on the same neutral point as the down elevator example.
And a closeup of the highlighted area.
You can see that the control rod is one again interfering with the seat pan. However, less so than the down travel limit. For max Up elevator the overlap is 0.063". For max down elevator it is 0.127". Changes to the neutral point could improve one or the other, but not both.
My conclusion is that it is not possible to reach max up and down elevator deflection with the RV-6 control geometry per plans.
The next step is to see what is the max possible deflection without the noted interference.
It seems where I went wrong was to make my elevator stops before completely rigging the elevator controls. I should have left the stops long and trimmed them once I had everything set up and could make appropriate adjustments. For my RV, I need to make new up and down stops to something less than max deflection, but no less than minimum. Based on what I have seen already I think I will have to remove around 5-10 degrees of total elevator travel, but that is just a guess at this point.
I would really like to know how much up/down travel some completed RV-6s have for comparison purposes. Are builders generally ending up with something close to Minimums?