Using the hook and twist compressor may cause damage (small nicks) to the spring but it's quick and easy. I used one for years but have broken several springs down the road, can't say if it's related or not.
I decided to make a lever type out of an old rocker arm welded it to a rod. Cut a large flat washers in half and weld to the sides of the rocker to press on the retainer. It's a two person job to use it though, one to hold the arm down and the other to remove/replace the clips.
Either way you will need an air hose adapter to charge the cylinders during the operation.
