Winter dog training/walking gloves?

Hello! I am a dog walker in Canada and it starting to get really cold. I handle a viper long line with my clients and train while on walks. My hands are always slimey from dog treats and slobber, and then they have to rub up on the frozen long line while handling. I often end my walks with numb and red hands. See, now I've used household gloves before, but they often get soaked or are super thick and horrible to train with!

Any recommendation for gloves that will keep my hands warm but is also practical while training?

Thank you guys so much!