It doesn't matter how well you adjust the Roadracers if there is only a tiny clearance between them and the tyres. As soon as your tyres pick up bits of sh*te off the road, the noises start. This isn't the fault of the product - the bike was not designed to have mudguards fitted in the first place. You have to choose whether you can stand the noise, or choose an alternative product. If you have a few extra mm of clearance then the Roadracers can be set up to be noise-free.
I am a bit hard of hearing so I don't notice minor noises but I do hear the louder ones.
I always use a garden spray to clean under the guards after every mucky ride and that definitely helps to keep the noises down.