[bruceh]

The instructions are pretty vague here. They mention putting a single washer on the rear stop, but there is no dimensional guidance on just how far to the left the vertical stabilizer should be at its leading edge relative to the center line of the fuselage. The F-981 attach plate is offset 1/4", but how does that relate to the dimensions of the offset farther forward at the leading edge?

Is there a critical offset dimension?

 

[Dave Cole]

The 1/4" offset sets the angle

The F-981 attach plate is offset 1/4", but how does that relate to the dimensions of the offset farther forward at the leading edge? Is there a critical offset dimension?

The attach plate offset of 1/4" sets the correct angle, so you don't have to measure it at the leading edge.

 

[rzbill]

There are two pieces of data you will have to choose between or call Vans.
As you stated, the joggle plate for the front spar is offset 1/4". While reading my -7 instructions (prob same for 9) I found a passage that stated 1/4 offset for the leading edge (not the spar). While the stab position would be different between the two, its not likely large enough to be an issue. One would have differing trim from the other. I chose to measure and set the leading edge position 1/4" offset. If it turns out that I need a big trim tab, I'll probably buy or make a new joggle plate to move the stab anyway so the choice was not a big concern.

YMMV.