If your pot started draining while you were watering that is a GOOD mix. You don't want a heavy soggy soil mix. Yes you will have to water more often but in the winter it won't be that much.

With that kind of mix it's almost impossible to overwater but still...just water when dry.

In the cold weather you don't have to worry about getting the leaves wet. In the warm months, when the temps are in the 70s at night, water on the leaves at night encourages black spot--a fungus that kills the leaves.

Roses are heavy feeders and like lots of water. If you have good drainage, which it sounds like you do, I would water at least twice a week in your area. You are in zone 10,no? When do water you want to make sure it is thorough, which means that water should run out the bottom of your pot, not necessarily when you are watering, but soon after.