i found the best way to mix sugar syrup was a burco boiler
2-1 ratio put the sugar in and then add the water. i used to turn it on at the plug and heat it up. but found that mixing it cold was just as good. all you need is a good stick and give it a mix every hour.
this saves on the electric bill
but i run about 80 hives if you just have a few then a saucepan and heat it gentley