30 years ago I used a tin of proofide, and the home oven set at 100 F degree warm temperature .
slathered a big dollop of the Brooks treatment in the under-side of the saddle .
and put it in upside down on some aluminum foil in a cookie sheet
the warmth melted the waxes in the proofide ,
and the warm leather soaked it up like a sponge , let it virtually saturate the leather.

Did little to it since, though when its wet out , I put a plastic bag over the saddle ,
and have toured for weeks in wet weather
with the poly bag over the saddle, and it has been fine..
no reason to take poly off then, since I Got rain gear over-trousers on anyhow..

in fact since thefts of the saddles have been mentioned ,
the plastic bags have an added advantage.. hiding the thing.