I'm no expert, but I figure the people who make the saddles are.
From the Brooks website:
Breaking-in a BROOKS saddle
There are many facts and fables on the internet as to how best treat a leather saddle but the concise answer is that the leather should never become soft, more so it should form to your anatomy. Trying to accelerate the breaking in period with use of substitute oils and waxes will cause the leather to soften and essentially become a hammock. Whilst some argue this is comfortable, they have missed the philosophy behind the use of leather.
http://www.brookssaddles.com/popups/...uti.html#treat

I have the utmost respect for Sheldon Brown and I use his website often for information and advice. But I have to disagree with his Brooks break-in advice.