I carelessly disassembled the linkage on my 1980 resto project and spent a solid hour getting the 'self park' feature to work correctly again - a royal pain. Follow the FSM if you start really taking apart the FJ40 wipers. The manual shows you how to set up the wipers before you disassemble.
I don't know how you can adjust the sweep, other than having the wipers sit higher up on the glass when parked.
Steve H. - KE0KNH
Colo Springs, CO
'78 FJ40, '89 FJ62, '98 4Runner