Chapter 111
When to Perform the Evening Rule
It seems to me you give yourself little sleep (from 10 to 1 o’clock past midnight). You could perform the night rule in the evening and then sleep until the morning service. But since you write that you are accustomed (to rising at 1 o’clock and performing the rule), it is difficult for you to change the order.
(Letter 2. Vol. 1, p. 8)