Optimizing Nodequeue Database tables

I suspect that the tables in the Nodequeue module can be optimized, but I'm not sure how to start. Nodequeue allows people to create arbitrarily ordered lists of nodes, and consists of queues and subqueues. A subqueue is a distinct list of nodes that inherits properties from its parent queue. Nodequeue's Smartqueue API allows modules to define new types of subqueues, such as a subqueue per-user or for each taxonomy term of one or more vocabularies. Below is the desc output of nodequeue's tables. nodequeue_subqueue joins to nodequeue_queue on the qid. nodequeue_nodes often joins against the node table on nid. Any suggestions would be appreciated by me and nodequeue's decently sized user base! Thanks!

mysql> desc nodequeue_nodes;
+-----------+------------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-----------+------------------+------+-----+---------+-------+
| qid | int(10) unsigned | NO | | | |
| sqid | int(10) unsigned | NO | MUL | | |
| nid | int(10) unsigned | YES | MUL | NULL | |
| position | int(10) unsigned | YES | | NULL | |
| timestamp | int(10) unsigned | NO | | 0 | |
+-----------+------------------+------+-----+---------+-------+
5 rows in set (0.00 sec)

mysql> desc nodequeue_roles;
+-------+---------------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+---------------------+------+-----+---------+-------+
| qid | bigint(20) unsigned | NO | MUL | | |
| rid | bigint(20) unsigned | YES | MUL | NULL | |
+-------+---------------------+------+-----+---------+-------+
2 rows in set (0.00 sec)

mysql> desc nodequeue_queue;
+----------------+------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+----------------+------------------+------+-----+---------+----------------+
| qid | int(10) unsigned | NO | PRI | NULL | auto_increment |
| title | varchar(255) | NO | | | |
| subqueue_title | varchar(255) | NO | | | |
| size | int(11) | YES | | 0 | |
| link | varchar(40) | YES | | NULL | |
| link_remove | varchar(40) | YES | | NULL | |
| owner | varchar(255) | YES | | NULL | |
| show_in_ui | tinyint(4) | YES | | 1 | |
| show_in_tab | tinyint(4) | YES | | 1 | |
| show_in_links | tinyint(4) | YES | | 1 | |
| reference | varchar(255) | YES | | 0 | |
| reverse | tinyint(4) | YES | | NULL | |
| i18n | tinyint(4) | YES | | 1 | |
+----------------+------------------+------+-----+---------+----------------+
13 rows in set (0.00 sec)

mysql> desc nodequeue_subqueue;
+-----------+------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-----------+------------------+------+-----+---------+----------------+
| sqid | int(10) unsigned | NO | PRI | NULL | auto_increment |
| qid | int(10) unsigned | NO | MUL | | |
| reference | varchar(255) | YES | MUL | 0 | |
| title | varchar(255) | YES | MUL | | |
+-----------+------------------+------+-----+---------+----------------+
4 rows in set (0.00 sec)

mysql> desc nodequeue_types;
+-------+---------------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+---------------------+------+-----+---------+-------+
| qid | bigint(20) unsigned | NO | MUL | | |
| type | varchar(255) | YES | MUL | NULL | |
+-------+---------------------+------+-----+---------+-------+
2 rows in set (0.00 sec)