I don't know much about the Brooks Cambium, but, FWIW... I only ride leather with no padding, usually just 2 layers of Lycra. Shorts and base layer or just 2 pairs of shorts. It really allows for good airflow and keeping things dry. But leather can be softened with mink oil or similar. People caution against doing it as it will shorten the life of the saddle from 20 years to 10 or so. But, once they are supple and conformed to you, nothing is better IMHO.
Now... I had to harden the heck out of my posterior to do so. And there have been times where I've had blisters due to having the tension too tight along with 100 mile days on mountain roads. If I do 30+ mile rides on successive days, I will start to get some tenderness. but it is not debilitation. I have some moleskin tape that does wonders.
Hope you get it figured out.