I have ridden my 6 weeks old Brooks B17 saddle about 300 miles some of which were in hard rain. It got an initial top and bottom treatment with Proofhide and then several follow-up applications on the top. But the saddle has developed a noticeable sag in the middle and I tend to slide into the sag. Raising the nose keeps me in place but causes other discomfort. I have read the late Sheldon Brown’s recommendation discouraging adjustment of the bottom bolt and several other posts that describe lacing a Brooks saddle’s skirt. Is it normal for a Brooks as new as this one to sag? Incidentally, I do not qualify as a Clydesdale.