I too suffer from Raynaud's Syndrome, I am typing this wearing fingerless gloves and fluffy thermal socks over my (thick) tights.
The only practical thing you can do is physically keep your body warm. I have drawers of thermal socks, fingerless gloves and thermal vests, plus throws, so that i can easily add an other layer and, most importantly, plan ahead. I have knitted gloves tucked into the glove compartment of both mine and my husband's car.
In winter I always have gloves in my handbag. Even when the weather is quite warm, I will always have an extra layer tucked away somewhere where I can easily access it.
When Raynaud's strikes, despite my caution. I fill a mug with very hot water and put my fingers in it, until they unfreeze.
Good luck
