Alex. Could you not make an xtreme brush that has a higher density of bristles as an in between the xtreme and SL? I've had to put a SL on last week because of all the bad weather as the xtreme just wasn't up to it, but the SL just feels like a brick in comparison. I think an xtreme with a weight of 200g ish inc socket, jets, tubes and tee piece would be just about right.