The accumulator and spring are a cushioning device for 1-2 and 3-2 shifts and if the spring is removed for firmer shifts the accumulator should be blocked from moving.
The blocker can be anything from a section of tubing to a peice of 1/2 pipe.
The accumulator piston should be blocked in the down position.
There is a specific length it should be but I can't find it right at the moment.
Some block it up and some block it down.
B&M shows to block it down, but I have never seen it make a difference either way.