This is the procedure I did to adjust the valves...rotate the engine twice.
At #1 TDC adjust these valves;
Intake: 1, 2, 3
Exhaust: 1, 5, 6
At #4 TDC adjust these valves;
Intake: 4, 5, 6
Exhaust: 2, 3, 4
Ok so after #1 TDC rotate the engine once and #4 is at TDC. Between #1 & #4, is #6 at 120° and #5 120° from #6 Then the same for #3 and #2...120° apart after #4 TDC