The one to remove is a 50x50mm square tube around 750mm long and the base is around 100mm square (125mm would be a better size) The square tube I used to fit the collar is 40x40mm with a washer welded on the bottom to contact to collar squarely.
Yeah I guess so, be sure to not hit the end of the spline directly, any "mushrooming" on the spline end and you can't get the axle back in the differential side gear, use a piece of wood or brass between the hammer and axle shaft if you must strike it. You will need a bit of force my press is good for about 6t and they can be tight. Carefully cutting the collar works too if absolutely necessary.
