as FOH stated, materials with low gas-flow resistivity (eg, pink fluffy attic insulation) are most effective for LF bass traps compared to OC703, OC705, etc.
even 34" corner chunks made with pink fluffy will perform better. if you stack cuts of pink fluffy, you need to add horizontal support every few feet such that the weight of the upper layers do not compress the layers at the bottom.
it is more wise to 'hang' the pink fluffy from the ceiling down, such that there is no need for the horizontal supports or compression.
eg, if you have an 8ft ceiling, then you will hang the first piece from the ceiling (8ft tall) all the way into the corner. you will need to cut the width down to say, 4" or so for the first first layer that is deepest into the corner. the next layer you hang (as the corner opens up), will be slightly wider (8"), and then keep adding layers until you are at 34" wide (faced), or extend even further if you have the room.
while it may seem unconventional that lower GFR material is more effective at LF absorption, like many things in acoustics, what is assumed or intuitive is not always correct.
use the cheaper (and more effective) pink fluffy attic insulation for corner porous bass traps, and save the expensive OC703 for broadband specular reflection absorbers.