your mix sounds fine
Check to see if it needs water daily, stick your finger in deep into the mix. Water only if it needs it.
Initially, it will not use much water, you might only have to water every other, every 3rd day, maybe even less. BUT CHECK DAILY.
Once new roots begin to grow, the tree will begin taking up water more quickly, the mix will dry more quickly. You will have to water more frequently. This is the reason you need to check daily, but only water as needed.
Junipers can absorb water through their foliage, that is the reason for misting. I would not mist more than a couple times a day. Morning and late afternoon. If you are in a suburban or rural area where the dew at night is heavy, you won't need to mist as often.