Making content_access work with OG and TAC

I've been able to successfully get OG and TAC to cooperate with respect to access control. You've probably seen the discussion here: http://groups.drupal.org/node/3700

I really like the functionality you've put into this content_access, and have been thinking of how to get it to work as well.

I've been looking through the code and can't seem to see what I need, which is:

A way to return whether, according to content_access, a particular user has permission to execute a particular operation on a particular node. Something like a hook_access ($op, $node) (http://api.drupal.org/api/5/function/hook_access) that will return simply true or false.

I looked at content_access_node_access_records, but so far the following code doesn't seem to return anything at all:

$node = node_load(arg(1));
$grants = content_access_node_access_records($node);
print_r($grants);

What I do in my current nodeapi code is query OG and TAC and see what they return. If they both return true or null, then we're good. If one returns false, then the user can't access the content. Pretty simple. If I can figure out a query for CA (content_access), I'd happily add it to the mix.

Here is an example of the check I run for OG. I'm not suggesting I do this exactly for content_access, but something that will give me similar results.
<?
/**
* Called by og_user_roles_nodeapi('access')
* To check og access permissions
*/
function og_user_roles_og_access_check($op, $node = NULL) {
global $user;
$uid = $user->uid;
if ($op != 'create' && $node->nid && $node->status) {
if (isset($user) && is_array($user->og_groups)) {
$gids = array_keys($user->og_groups);
}
else {
$gids[] = 0;
}

if (isset($user) && is_array($user->roles)) {
$rids = array_keys($user->roles);
}
else {
$rids[] = 1;
}

// if this node has groups or is a group, then use group sql, else use non-group sql
$groups = $node->og_groups;
if ($groups || $node->type == 'group') {
$sql = "
SELECT COUNT(*) FROM {node_access} na
LEFT OUTER JOIN {og_uid} ogu on ogu.nid = na.nid
LEFT OUTER JOIN {og} ogm on ogm.nid = na.nid
WHERE (na.nid = 0 OR na.nid = %d)
AND ((na.realm = 'og_public' and na.gid = 0)
OR (na.realm = 'og_subscriber' AND na.gid in ('%s'))
OR (ogm.nid > 0 and (na.nid in ('%s')) or ogm.directory = 1)
OR (na.realm = 'term_access' AND na.nid in ('%s')))
AND (na.grant_$op >= 1 OR (ogu.is_admin = 1 AND ogu.uid = %d))
";
$group_ids = implode(',', $gids);
$result = db_query($sql, $node->nid, $group_ids, $group_ids, $group_ids, $uid);
}
else {
$sql = "
SELECT COUNT(*) FROM {node_access} na
WHERE (na.nid = 0 OR na.nid = %d)
AND (na.realm = 'term_access' AND na.gid in ('%s'))
AND na.grant_$op >= 1
";
$result = db_query($sql, $node->nid, implode(',', $rids));
}

$output = (db_result($result));

if ($output == 0) {
return FALSE;
}
if ($output > 0) {
return TRUE;
}
}
}
?>
If you can give me some hint as to how I could get similar results from your module, I'd appreciate it.

Thanks for any assistance you can provide.