On SearchWP activation, set the defaults for my custom post types.

searchwp-custom-settings.php

<?php

namespace Soderlind\Demo\SearchWP;

add_filter( 'searchwp_custom_field_keys', __NAMESPACE__ . '\\on_searchwp_custom_field_keys' );
add_filter( 'searchwp_initial_engine_settings', __NAMESPACE__ . '\\on_searchwp_initial_engine_settings' );
/**
 * Add custom fields to the search index
 *
 * @param array $keys
 * @return array
 */
function on_searchwp_custom_field_keys( $keys ) {
	$keys[] = 'ingress';
	$keys[] = 'hogan_%'; // % = wildcard. I have multiple custom post types prefixed hogan_
	return $keys;
}
/**
 * On SearchWP activation, set the defaults for my custom post types.
 *
 * @param array $settings All of the default engine settings.
 * @return array
 */
function on_searchwp_initial_engine_settings( $settings ) {

	$post_types = array( 'post', 'page' );
	foreach ( $post_types as $post_type ) {
		$settings['default'][ $post_type ]['weights']['cf'][ uniqid( 'nettsteder' ) ] = array(
			'metakey' => 'ingress',
			'weight'  => 40,
		);
		$settings['default'][ $post_type ]['weights']['cf'][ uniqid( 'nettsteder' ) ] = array(
			'metakey' => 'hogan_%',
			'weight'  => 10,
		);
	}

	return $settings;
}