If possible it would likely be best to pivot out the darts if your pattern had them.
You would have to assess each pattern and decide on what thickness of leather would work best for example if your pattern was to fit close to the body you would want to use a thinner more pliable leather.
you would have to decide on what closures to use most patterns have the seem allpwance printed on the pattern adjust the seam allowance to be wider or narrower.
i recommend using scrap leather and make a sample before using more expensive stuff you will want to make your sample using the leather with comparable properties. Eg of you want to use a thick, stiff leather making a sample with thin pliable leather will help with construction sequence but likely won't be useful in terms of fit, drape etc
Do you have a specific pattern in mind?