Soil mix

What mixes do folks use? I have been using a 50/50 split of miracle grow succulent and orchard bark mix for twoish months, after seeing a couple people recommend. My Hoyas are in clear nursery pots so I can keep an eye on the roots/soil, and the soil looks dry in this mix 24 hours after watering for some of my guys.

It seems my smaller plants arent doing great in it. My crassipetiolata's leaves were starting to shrivel when I had just watered it 5 days ago so I gave it a good soak. My Krohnianas aren't looking great. All in 2 inch pots.

I have another crassi in a 4 inch pot in the same mix and it seems to be thriving. Shooting out new leaves like crazy.

Wondering if the mix isn't great in general? Or maybe the 2 inch pots are just too small for the orchard bark and it's taking up too much of the space.