Mixing plaster in a plastic bag

I'm not a plaster master, so I don't know if this is a good or even original idea.  By mixing plaster in a plastic bag, it seems easier to remove bubbles from the mixture, while pouring is much more controlled.  It's the same idea as using a garden watering can for pouring glaze:  You pour from the bottom where pressure is highest and bubbles are fewest.

• Add measured amount of water, then plaster into plastic bag supported by bucket.

• Let sit for a minute or two, then stir as usual, being careful not to entrail air into the mixture.

• Lift the bag out of the bucket, checking for leaks.

• Check for air bubbles in the mixture.

• Air bubbles trapped in the plaster mixture.

• Pat the plastic bag, vibrating the air bubbles to the top.

• Cut a small corner off the bag, and control release of plaster using fingers. Pour in a controlled fashion against a wall without splashing.