Moroso's accumulators are the same diameter, volume only varies due to length. If I remember correctly, the Accusump's are almost the same diameter as the Moroso, just different lengths for the different volumes.
Supposedly any size all the way up to the 3qt will fit up there, but I know the curvature of the vent area makes the 1.5qt a tight fit to get on the mounts, so when the lenght is doubled I can only imagine that a custom mount would be needed.
Any size you choose should be usable in this spot, some will just be easier to mount.
