Nice write-up!

Might be easier to loosen the water pump pulley bolts while the belt is in tension.

Alternatively you can put a long screwdriver shaft across two bolt heads and loosen the other bolt/s. Move the screwdriver shaft among bolt head pairs to loosen the remaining bolts.

The tensioner arm hole goes through to the timing chain cavity so be careful how you clean the threads.

The tensioner arm bolt torque spec is 100Nm/73 lbft... into the aluminum front cover

Sixto
93 300SD