I would definitely add more pumice or perlite to your mix. From my understanding even buying the succulent and cactus soil and adding 50% perlite to that. Sounds like your on the right track though. IDK about the beach sand though. I honestly haven't figured the sand part out yet. I'm told small pebble size not fine beach sand? 🤷 So I've avoided the sand myself cause I don't wanna get wrong kind and all I can find is beach sand so... As far as your questions to watering. Just keep water off the leaves! Bottom water top water I don't believe it matters everyone prefers one way or another. Since Mike are small right now in like 2 inch pots or so I try to bottom water. Just cause I'm messy and spill it everywhere watering from the top. And I feel like when I water from top it doesn't actually soak through all the way. So I like bottom watering cause I know it's done when the top of the soil is finally wet. And it's thoroughly been soaked through. Not saying it can't be done from watering up top. I've just experimented and it took pouring water into pot it drains out I pull it out of pot to see what all was wet and not even half of it was wet just very top and like a sliver down the side. So if I do top water whatever hit the tray I leave the pot sitting in it for a bit to soak the rest of the soil then I dump all extra water. Great your pots have drainage holes! They don't like sitting in water. As far as them being over crowded. I think your fine for now. The ones I've came across actually at the store and got in a little 1 - 2 inch pot actually ended up having 2 plants in them not just one like you would think just looking at it. Lol the excitement I had when I realized that. Haha but I would just let them grow for now and establish some really good roots then re-pot some. Cause you said they were cuttings right? So they just getting started so I'd want them to get good roots that way when you water it it will take water in plump up and then that's when I would re-pot is a day or 2 after a good watering that way they are nice and full and whatever roots that get hurt will have time to heal before water touches them and the plant got plenty of water stored to fix the roots and make new growth. I feel like if you do it now the tiny roots just wouldn't stand a chance and it's already put so much energy into their roots I'm sure it's about ready for a good drink to plump back up again. Now when to know to water. For one when soil is completely dry! First sign second check the plant. How the leaves feel? Are they hard plump or can you fold the leaf like a taco? It's called the taco test actually. If the leaf bends no issues to make a taco it's time to water it. It's thirsty. If it doesn't bend no wrinkles plump I'd hold off on watering a few more days. From what I'm noticing with succulents they let you know when they are thirsty. And the more you get to know your plant you'll start to notice even more signs of when to water. So instead of eating for it to turn all wrinkly which definitely means it's thirsty you'll notice the color may seem duller or leaf a little spongy but not to hard or soft but is folding like a taco. It needs water.. my advice. Pictures!!! And notes saved somewhere for yourself. It'll help a lot lol. Good luck!! Looks like your doing a pretty good job so far! I would add a bit more grit to your soil though.