Alarm_1 is set for 04:30 and a DateTime variable connector is created.
When Alarm_1 is added to a Days of Week Schedule it reads it's value as 03:30 (but does not change the variable's value of 04:30) and sets the cron string to '0 30 3 * * ?'. I can't think of any circumstance where I'd ever set a date and time or just a time and want it to correct for DST. DST should only adjust the clock twice a year. Any schedules should be unaffected.
Once the variable connector is used it does not show up under triggers. Only the days are shown.
Changing the variable's time does not automatically update the cron job. Changing the variable to another time variable also does not update the cron job. Opening the rule and clicking 'update rule' does update it. If the variable is updated with a new time and 'update rule' is clicked the new time is set and not adjusted for DST.
The rule does fire when the cron string matches the current time.