Was the leather, you bought, meant to be used for upholstery? If so, then it should not need any "tuning up". I'm not sure what you mean by "tuned up".
Leather purchased from an upholstery supplier is ready for application and use. No treatment, of any kind, should be needed to be performed or applied on it. Cloth fabrics will have notations as to whether a ScotchGuard type treatment has already been applied or not, but leather doesn't require such consideration(s), even distressed leather. You should be fine with applying the leather, as is, onto the chairs and, once applied, you are good to go.
For care in the future, if need be, check out this site.
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if you plan on using decorative tacks as trim, I recommend buying some from a local upholsterer, not from Wal-Mart or any like outlet. The French Natural brass tacks are typical for that application. Also, unless you have a tool to assist in applying these kinds of tacks, use needle nose pliers to hold the tack stem, for alignment, before nailing. You're likely to bend the stem if you try to use your fingers to hold the tack in position. You don't want to mar your leather with a bent/mis-driven tack. Leather is not as forgiving as cloth fabric. Tie a sturdy piece of cloth, like denim, on your hammer head so that the hammer's metal head doesn't scratch/damage the tack head surface. An upholster's tack hammer has a nylon tip, to prevent this kind of damage. Sonny