Hey Paul, I have and use one similar to the bottom one, with the two threaded shafts and the links to attach to the spring. When you are getting ready to attach it to the spring, you have to take into consideration not only the fit on the spring as it sits on the strut, but whether or not your selected position for the links will let the spring compress enough to get the strut out. In the wrong place the link can interfere with fully compressing the spring. There is no harm if you put the links in the wrong place, you just waste time uncompressing the spring, relocating the links, then compressing again.

Put one shaft on each side of the spring, and compress/turn shafts equally to compress the spring symmetrically. Like two or three turns on one side, then on the other, etc. That is all there is to it.

When I did Brunhilde's struts last year, I found it was nowhere near as bad or difficult as I had expected. Don't forget the boots around the strut shafts to keep them clean, or you will be doing this again in less than a year.
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1955 Human, Scott; 1991 745 Turbo, Brunhilde; 1990 745GL, Snuggle Bunny