Which ditching bucket for CAT 312 Excavator what size???

Need to purchase a ditching bucket for the CAT 312 Excavator.
Been on internet looking at buckets.
examples
60 inch wide 630 lbs 1/2 cubic yard capacity
68 inch wide 722 lbs .58 cubic yard capacity
There are wider buckets 80 inches.
Would some people communicate what there thoughts are on a size of bucket for cleaning the ditch along side roads.
What has been your experience bigger better or dangers of to large (wide) a ditching bucket.
The buckets sure do not have much capacity my 43 inch...

Which ditching bucket for CAT 312 Excavator what size???

Which ditching bucket for CAT 312 Excavator what size???