the Clack Ws1 is the best valve available, so you're good there. it will certainly need to be disassembled and cleaned, and likely need a new injector. I get all my clack parts from softenerparts.com the guy there is great and will help you with whatever you need resin too. get the Clack service tool too. youtube videos show you exactly what to do. soaking iron stained parts in a strong iron out solution overnight will clean them right up.
since your softener is in the garage it will be easy for you to roll it outside and dump it into an old pillow case to collect the resin. it's still a bit of work to clean it out. I just bought a new tank, riser, etc, put the resin in and got it all staged, and then just swapped out the tanks to minimize downtime. mine is in basement, much more difficult to get outside.
you really should do an iron test so you have a sense for what you're dealing with. hardness too. so you can program the valve correctly and avoid the mess you currently have. high iron is probably why the softener is so big, and why your neighbors regenerate every night. the iron test strips don't work, you need a proper test kit or send it to a lab. or ask a local water company to test it most will do it free if you bring them a sample.
the nasty crud descriptors in your posts make me think you have iron bacteria too. that will make your headaches much worse. fill a glass with raw well water and let it sit overnight. if it turns cloudy with orange crud at the bottom you have iron bacteria. brown slime in your toilet tank is also a sign. shocking your well with bleach will kill off the bacteria for a while.
keep an eye on those canister filters they will clog up quick with iron crud.
Working from bottom up,
I do change my 4.5x10" filters regularly, even before I see pressure drop on them. I am considering replace those will a whole house back washing filter before the softener though. Less maintenance.
Iron bacteria is not bad, was stays clear, showers are good no. However I did deal with it a year or so ago. Hasn't come back since.
I have been using this little test kit a water guy near me gave me. Think I need more than this? (see attached pic)
Im leaning on doing the iron out run now to see how it does.