How long after fundoplication do you get the full benefits of the surgery?

Varies: The fullness can be highly variable. How tight vs how lose the wrap was made, how much postoperative swelling is present and the length of the actual wrap can play a role. Generally, patients will reach a baseline 3-4 months after surgery when all the swelling is gone. If the wrap was made to tight, the patient may have long term problems with swallowing or excessive fullness.

Almost immediately: The operation will provide protection from reflux immediately. However you experimce some pain with eating, feeling full, and some esophageal spasm for a few weeks but you should not feel reflux symptoms.