Currently, the Speaker doesn't have that authority, but there is nothing preventing the House from giving the Speaker that power.
As for the holding of votes at 3 p.m., you're right; that practice was adopted a few times. It works well insofar as the bells are generally not rung. I would point out, however, that a party wanting the ringing of the bells can always demand it. In order to ensure that voting can take place without the bells being rung, the possibility would have to be included in the Standing Orders.
That said, as you pointed out, when a large number of votes are taking place, the time required for that is added to the end of the day, as is the practice. That's another consideration to take into account.