It will be more moisture retentive than the straight gritty mix, so yes, less frequent watering required. But fertilizing is fertilizing and really has nothing to do with the soil mix. Any containerized plant will need fertilizing.....cacti and succulents just tend to require less than most plants.

And skip the worm castings. The particle size is just too fine and they will impede the fast drainage these plants require. If you want to benefit from them, make them into a worm casting tea and use them to fertilize the containers.

Keith, I tried the "prototype" gritty mix too, several years ago, with Turface, chicken grit and bark. I sifted and washed, and I AM the type who fertilizes appropriately with a non-organic mix. But...I didn't have the kind of success I wanted, and not the kind I saw other people on the old Garden Web having. First I minused out the bark. Then I experimented more. After a couple of years, I do have a "gritty mix" that works moderately well for me. It's pumice, manna pro chicken grit, and Turface in a 2:2:1 proportion. Also, I sometimes use those ingredients in a 1:1:1 formula. Not saying it's great -- just that I can manage it pretty well. I still do fertilize with every watering.

Can't speak to coco coir or worm castings; have never used. But....my point is, I played around with adding this, subtracting that, changing the proportions. My own feeling is that if you use an inorganic plant mix that supplies no nutrients, you have to supply them. I do it lightly at each watering because that was how I learned here. But there are probably other ways and frequencies.

gg and robin offer excellent advice. My own mix, while like Robin's and containing a lot of inorganics (equal parts Turface MVP and #2 {ideally} poultry grit) with some organic matter (sifted top soil), is ideal for almost all C&S.

If you're growing more tropically-inclined cactus, leave the bark chunks in from commercially-produced C&S mixes. Otherwise, get rid of anything that's over 1/2" large, and then cut the remainder with 50% perlite. That's an easy way to achieve a good starting soil, but as noted there are endless variations, depending on amount of sun, overall weather, wind, surface around potted plant, humidity, etc.