Another thing to mention, if you're trying for low maintenance moms then the mini-SIP + organic soil has worked well for me. Part of the process of rotating the mother plants and replacing them is that also provides the opportunity to 'refresh' the soil as it will get depleted over time.
When designing your mother plant soil, I try to look for slow release amendments or those with other benefits like buffering or IPM (i.e. neem is good for both an input and pest control). I've also tried to use products like OneShot from Nectar of the Gods, etc. Would be nice if we could find something tailored to slow release for mothers, not vigorous veg/flower cycle use.
I also highly recommend the 'Mother Plant' A/B nutes - and with my recent experimentation it can work beyond just mothers (you should see what it does in a cloner once they grab ahold with those water roots). I was using that in multiple ways lately but for moms when the organics show hints of deficiencies or just fizzling out - that can cover ya until you can make new moms or amend the soil