Now that I think about it later, maybe the 154lbs is the force that the cyls themselves are capable of exerting @20Bar... but of course you're not going to be able to lift 154lbs out at the bucket's edge.
pie x r squared x 280psi x 2 cyls = ?
If the lift cyls are 15mm bores each, then two of them would push 154lbs together.
Knowing the stick cyl bore on my Vario is 21mm = 0,8268 inches
3,14 x (0,4134 x 0,4134) x 490psi (35Bar) = 262.95lbs force
That stick is (approx.) 4" above the pivot point vs 16" below to the ripper point, would the formula for positive & negative leverage be as simple as 1:4? If so, then at the point of the ripper it's 65.74lbs force. That seems plausible to me, having seen it rip the hard ground!