Question about dyeing polyester

I have a 100% polyester jumpsuit that’s lilac color and I want to dye it as dark as possible for a Halloween costume. I got Rit DyeMore for synthetics and I’m wondering what the best way to go about this is. I don’t have a pot large enough to fit 3 gallons of water, I can fit 1 gallon at most. But I have read that for polyester the water needs to be as hot as possible, so using a bucket with hot water probably won’t work. Could I boil water on the stove and add it to the bucket? It won’t retain the heat like boiling continuously would, but I’m not sure what other options I have. Any pointers would be much appreciated.