When I get a new saddle or piece of tack that has potential but needs some conditioning I use a multi step formula.
If the saddle is really dirty I'll first use some warm water and saddle soap to get the grime off. Then I'll use a glycerin spray and work it into the leather. I like Black Rock (which is kind of expensive and sometimes difficult to find) to finish it off - It really softens the leather and leaves a nice patina. If you can't find Black Rock, then I would use some Neatsford oil to finish it.
I like to clean my leather with Murphey's Veg. Oil soap, that you get in a grocery store. It smells great, cleans it without drying out the leather and it's cheap!
Then I oil with neatsfoot oil (but I'm not worried about keeping light tack light colored-I prefer the darker colors!). If the leather is really dry, I slather the oil on, let is soak overnight, and repeat the next day. Then I buff out any excess with a towel.
If you are worried about keeping a light color in your tack, Lexol has some special products you can get. But the bad thing about light leather is everything darkens it-the oils in your hands, dirt..sunlight even darkens it. I know a lot of people that want to keep a show saddle light dust it with baby powder to keep it from squeaking but never oil it all. Me..I prefer to oil it anyways so it will last!