You need to be a little creative with the linkage. The servo arms for the elevator or the rudded servo need to be opposite each other. For 3d the longest arm you want to use has linkage centers 1-1/8" from the output shaft. If you have 1-1/4" arms you need to grind off the excess length from the end of the arm. The linkage rod angle won't be a factor.

For precision or IMAC stuff you don't need an arm longer than 1". In truth, for most 3d stuff the 1" arms work well on the 35% Giles. I don't believe I have a picture of the Giles with 4 servos in the tail, but I haven't found a need for dual servos in anything other than the big Sukhoi so far, although I'm sure the 40% Extra needs them. Let weight and balance be your guide to the number of rudder servos. If it needs the weight, use two. If it doesn't, use one. The plane will knife edge loop all day with only one good rudder servo. That's a pretty good test of what a rudder needs for servo power.