Make something to attach the loer ende of shock FIRMLY to table..it should not be able to kick sideways..very unsafe. '
Make a collar for the top end, easier if its machined.. needs a hole aboout 20 thou bigger than your split collars and a lip to hold the spring. this collar needs standoffs to a plate above it, with a stud welded in the middle..that fits into your drill chuck, use drill handle to compress shock and get collars out.
You need about an inch and ahalf of down movement , before taking shock apart, as spring get longer when decompressed. If the procedure is difficult or dangerous,lifting table may help.. I do mine on the lathe, then I CAN LET GO OF IT AND STAYS IN PLACE.
I use similar setups to remove valvesprings..