Oh wow, you are going for it in a big way, but once you have all the equipment it will make life easier in the long term and you won't need to keep faffing about with different waters. As the chap said on that video (watched it again last night, it is very good) even neos do better in remineralised RO water than tap water anyway. It also covered the different 'salty shrimp' remineralisers, ie GH+ for caridina, GH/KH+ neos, and another for sulwasi.
I had a quick look on my suppliers website and saw this so there is a product 'out there' that just does KH and expect you can get that from somewhere locally if you WANT to go that route, but it will probably be harder to get hold of than the GH/KH+ route (and can only see the 1 type), and the GH/KH+ route is easier anyway but it means you will be left with the GH+, though you probably still use that in the crystal shrimp tank so won't be a complete waste?? You may be right anyway that the KH isn't important so maybe wait and see if someone comes back with that info at this stage?
https://www.pro-shrimp.co.uk/water-treatment/1280-dennerle-kh-elixir-4001615016765.html
I am sitting here typing this to avoid the weekly task of culling 2 shrimps, it gets harder each week and I can't see any I want to get rid of as I only have pretty (adult) ones left from what I can see...................
Simon