How often are you planning to change springs?
Something like this would be fine for occasional use........
LINK
To be fair, I still use a pair of compressors made for removing a spring on a Mk1 Cortina, and although I have two pairs, it is fairly easy to see what is happening while they are being used.
The first floor mounted ones you linked to are very easy to use, I used mine to remove the strut top bearings from a pair of dead Rover 25 McPherson struts, which took less than a minute to set and secure the strut, and the same to compress and decompress the spring.
I then fitted the bearings to the struts from my wife's 75, it took slightly longer, but certainly less than 10 minutes per side.
Fabulous for moderate users, and better value for money than
THESE for instance.
Brian