[sc_rufctr]

20 ton should be more than enough for anything you're doing in the back yard.
(It's real easy to wreck anything if you're not careful and freezing parts overnight helps a lot.)

I bought a cheap arse 10 ton press and replaced the Chineseum jack with a Ford bottle jack.
I've had no issues doing a number of jobs over the years.
I also use a 1 ton arbour press that's very versatile for smaller jobs.