Measured, marked, drilled and deburred holes for bolting WD-812 rear control stick in WD-412B rear control stick base. Experimented with different assembly sequences to determine the proper way to install control column and sticks in fuselage. Sorted out connecting bolts washers and nuts for each assembly. Installed control column and sticks in fuselage. Some grinding of bolts will be necessary to create minimum clearance inside control column.