shift speeds/rpm

Yeah. Linkage adjustment check should be your first item to verify. I'm sure Trail Beast has done it a hundred times but he forgot to mention that the levers on the trans should be in the neutral position. It's usually easier to detach the rods at the shifter first. Locking the shifter with a pin through the the holes in the shifter locks it into neutral. Thrn adjust the rod length to line up with the holes.