It can be as beefy as it needs to be. There is no constraint there to limit the design.
It is actually an extremely flexible concept from what I can tell. Need a longer stroke? Add more angle to wobbler. Need more Torque? Expand the wobbler diameter.
There is a limit on the available angle that can be "wobbled". Once you exceed ~20 degrees IIRC, the displacements perpendicular to the stroke start causing problems.
I think the more interesting interaction is between the number of pistons and the size of the pistons.
It is actually an extremely flexible concept from what I can tell. Need a longer stroke? Add more angle to wobbler. Need more Torque? Expand the wobbler diameter.