It might be simpler then it looks.
2 tie down straps, 1 strap for each side of shock.
Tie down strap runs through upper coil (2nd coil in photo)
and both ends of the tie down are hooked to the bottom of the jack.
Ratchet strap only to take up any slack.
Repeat on opposite side with 2nd strap.
Use tails of straps to lash to pole for stability.
Now as you pump the jack , the straps are hooked to the
bottom of the jack and the spring will compress
Photo shows compressed spring with the collar ready to remove.
Let jack down to release spring.