Empennage: Horizontal stabilizer. Ribs and stringers riveted to front spar.

The ribs and stringers are riveted to the front horizontal stabilizer spar.  Was able to squeeze every rivet save four.

Where the spar attaches to the empennage's tail cone, there is a lot of reinforcement.  This suggests a lot of loading occurs here.  And there probably is.  However, the horizontal stabilizer from the -14 comes from the -9 (except the 4 inspar ribs, which are from the -10) and yet is not attached to the aft fuselage in the same way as in the -9.  This is why there are those square patches of 9 rivets on both sides of the doubler:  In the -9, these holes are to hold attach brackets.  Because the -14 has forward attach bars located on the aft empennage bulkheads rather than on the stab spars, those pair of 9 holes do not secure the attachment elements.  Instead, 1/4" holes are drilled into the doubler on each side of both spars so the attach bars on the bulkhead can grasp on to the horizontal stabilizer with AN4 bolts (a total of six, four aft and two fore).  This approach is unique to the -14.  Even the -10 has forward attach brackets on the spars.

Attachment approach used in the -14.

 

Here is the shop head side of all that.
 

The two inside "inspar" ribs each have four AN470AD4-4 rivets fastening them to the stringer web.  Because those two ribs are at a 12.5 degree angle, access to those rivets is a challenge.  I ultimately settled on the following approach and it worked well for me