A bent rod with a notch in the end, won't do it? https://www.youtube.com/watch?v=MIyESaecC2s
(They sell just the rod, and I have one laying around somewhere, but it's been awhile since I've needed one.)
I used a ratcheting strap to stretch the spring out and then a large screw driver to “ persuade “ it on on my old JD tractor. Be careful, this could be dangerous and is a tough procedure.
I was going to suggest a similar tool that I saw ETCG use on springs for a drum brake replacement, might be useful. I like the idea of coin spacers though!
Spring Pull Tool https://www.ebay.com/itm/Genuine-MTD-732-0571-Spring-Pull-Tool/232260443358?epid=1713027439&hash=item3613cd1cde:g:8G4AAOSwiYlaGIxS
I have and use three different sizes of these type of spring pull tools. work very well.
Also used a piece of looped starter rope many times, just make it into a loop, put on gloves, hook the spring and pull into place.
edit: I use these tools on lawn and garden equipment not farm tractors.