Upon close inspection of R-710 Rudder Horn Brace, measurements compared to those found on MIL-R-47196A "Preparation for and Instalation of Military Specification Rivets, Buck Type", it was determined that the edge distance of the match-drilled holes connecting R-710 to R-802PP Spar (fabricated holes) did not comply with safe clearance standards.
According to document, minimum edge distance of any dimpled hole receiving another dimple, measured from center of 3/32" rivet placed in dimple, to its edge margin should be 0.156". Measurements for R-710 holes, to their respective edges ranged from .106" to .147".
It was therefore decided to discard R-710 and order a new one directly from Van's Aircraft, and redo the trimming of the horns and its respective match-drilling of its holes with larger margin distance.