I have a Champion Flyer on my LHT with about 5000km on it. Most comfortable saddle I have ever used even if it weighs 850g.
It sounds to me like you are sitting too far forward on the saddle. You can either slide yourself back a little to sit behind the tensioner or raise the front in very small increments until you are naturally situated further back.
Where you sit on the saddle makes as much difference on at the saddle itself. The Specialized Toupe Gel is a good example. Your sitbones need to be right on the platform to be comfy.
Here is a photo of what your Brooks aspires to look like:
