We analyse the throughput-delay trade-offs that arise in an optical burst-switched slotted WDM ring, where each node can transmit and receive on a subset of the available wavelengths. Specifically, we compare SWING, an access control scheme that combines opportunistic transmission and dynamic reservations, with a purely opportunistic access scheme. By means of analysis, we highlight the shortcomings of the opportunistic scheme in terms of load balancing and fairness. We then evaluate the performance of both schemes by simulation under several traffic scenarios and show that SWING yields a good throughput-delay trade-off.