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.
BTW, 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.