Given that all the transactions would be executed at the same time, the rate set window could be quite short (for instance, bids and offers could be submitted over a 15-minute period, with the tender closing at 10.00 am). Each of these methods has its advantages and disadvantages.
Conducting the transactions over the phone is flexible and is most similar to current market practice, so it would be unlikely to require extensive changes to systems and procedures. However, it would be the least transparent, which may discourage participation from investors and necessitate more oversight of the conduct of market participants.