Serving Papers

What is the best way to make sure the defendant is served in a timely fashion? I would rather not have him served by the sheriff if I can avoid it (I don’t want to anger him more than he already is). However, he works during the day when mail is delivered and I don’t trust him to fill out and return the green card attached to a certified letter. Can I send the papers via UPS or another carrier service with signature or are my only options sheriff or USPS certified mail?

You may serve him via fed-ex.