How do you protect the underside of your brooks leather saddle? I'm new to leather saddles and I'm working on breaking mine in. I'm using a Brooks B17 Narrow.  I use clip on fenders with my bike when the weather is bad. However, sometimes I get caught in the rain, or hit puddles on otherwise dry days.   I know that I need to apply proofide to the top of the saddle to protect and condition it, but I'm not sure what to do about the underside.

What strategies are recommended for protecting the underside of your leather saddle?  

Would applying proofide to the bottom be appropriate to help protect it? Other suggestions?
Brooks recommends applying a layer of proofide to the bottom of the saddle. However, you should not wipe this layer off after it sets. Just leave it on, and it will protect the underside.

Personally, I also recommend fenders for a bike that you plan to use frequently in the rain. This will also drastically reduce the amount of water that splashes up into the underside of your saddle. However, only a "permanent" full-size fender will really provide this protection — removable ones don't protect the seat tube, and the spray from water hitting that is the primary source of the water that gets under the saddle.