I believe you need to look at the gform_after_submission hook.
You then use Gravity Forms rgar value.
Perhaps, you could use repeater field and add the oEmbed field into that?
<?php
add_action( 'gform_after_submission', 'set_post_content', 10, 2 );
function set_post_content( $entry, $form ) {
//getting post
$post = get_post( $entry['post_id'] );
//change the 4 to your gravity form field number
$number_of_posts = rgar( $entry, '1' );
#add the row to the repeater
$row = array(
'field_5d9470467aab9' => $number_of_posts #this is your repeater subfield key
);
$i = add_row('field_5d946796a4fd7', $row, $post_id->ID); #this is the main repeater key
}
Just an idea. You may need to play around with the concept!
