A notch smaller? as in cylinder bore?
The stick cyl is 22mm, which is nearly equal to 7/8; while the dual boom & bucket cyls are smaller... maybe 18mm... can't recall exactly, pretty sure it's 18mm.
18mm is good enough for bucket power, but depending on length of boom & stick & the weight of the two arms, plus what attachments you might use (my screener bucket is really heavy when full of dirt), dual 20's would be better.