Hey josh, yea I was testing with all subaru parts. The shoulder bolt is the bolt found on the other side of the universal joint that has the identical bushings. Its the bolt with the 10mm(3/8") shaft but the threaded section is 8mm(5/16".) Its the reason for the the two different sized holes in the linkage arm fork. I just took the fork attached to the tranny shift rod loose(by popping out the twin roll pins) and then spun it around the shaft 180 degrees(cause its drilled 10mm away from the tranny and 8mm next to it) and repinned it with that shoulder bolt inserted to see if the head would hit the side of the tranny. And I saw no probs. Im gonna take some pics and post them up to show you what Im talking about.
The bushings in question list overall length at either 1/2" or 3/4" with flange thicknesses of 1/16". The barrel in which the bushings are inserted is slightly over 1 3/8" and would need to accomodate 1 3/8" of the inserted parts of the bushings from each side for the 3/4" length bushings. So again unless I am missing something youd get near continuous bushing coverage through the barrel and maybe a bit more support for the load and have several more material options. Im not sure either if Delrin or Teflon bring anything additional to the table tho.