Ok, I get that. We are going to try removing the detent mech. first. We adjusted the 4 forward speeds as you outlined. The reverse levers were adjusted as both the lever on the trans. and shifter were engaged in reverse. So ixnay on the ackway.
we won't be banging on the cover.
Maybe I'm reading it wrong? regarding your shifter adjustment procedure...
looks like a case of back to basics is needed first, remove the shifter rods all 3, the transmission needs to have all gear lever positions, reverse included in NEUTRAL position
The shifter needs to be in the neutral position, you need to insert a rod/drill (1/4" IIRC) bit thru all 3 shifter arm pilot alignment hole, then adjust the shifter rod swivels/ends to fit freely into their corresponding holes, reverse included
Now if you have an aftermarket shift box with shifter stops, that will be another adjustment
Mike