Checklist/forms for a shortsale

I am wanting begin the process of a shortsale. I plan to offer 60k. Appraisal is 100k. Payoff is 80k. Should I shoot for lower? Also, does anyone have a checklist/forms for the shortsale process. Your help would be greatly appreciated. One more thing, I plan to lease the property back to the owner with an option to buy. Is there anything I should look out for?

Thanks again,