I did remove the spring on my 123 using the method you describe. I moved myself from the line of fire, secured the spring with chain and straps, and lowered the control arm.
That was 20 years ago. Had to do lower control arm bushing.
Had minimal tools and no internet.

I now own a mercedes type spring compressor. It certainley does make the job easier.
The tool rental part of this website has plenty available for little to no money except shipping.

I live sort of near you, let me know if you need to borrow mine and we can work it out.

Check local auto parts stores, especially NAPA or independant stores for the tool.

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80 300D 340K Owned 30 yrs
83 300SD 440K Owned 9 yrs - Daily Driver 150mi/day
02 Z71 Suburban 117,000
15 Toyota Prius 2600 miles
00 Harley Sportster 24k
09 Yamaha R6
03 Ninja 250