
Don’t use a furminator on a golden as it cuts the long guard hairs of the top coat and can take a long time for the coat to recover from this. Make sure if you take him to a groomer that they don’t use one on him.
One of my goldens coat became more woolly and thick and I got her professionally groomed a trimmed, if you can find one that knows how to groom a golden properly then that would be the best. I know there is a very good video on grooming a golden and using thinners on YouTube, wish I had saved it.
My current golden is not heavily coated and doesn’t take much with the thinners to have a reasonable effect. The rule of thumb seems to be to go with the direction of the hair not against it