For me mixing large amounts of colored icing never come out right. I make several smaller amounts in my small mixing containers. Sometimes i make them all in advance or not. Years ago, Karen summers showed putting your icing in plastic and rolling it up. Then i can easily drop them in a decorating bag. I can easily take it out and use the bag again. It’s also less messy. I use tipless bags with a coupler and tips because they are cheaper and easier to handle.