Many thanks for a useful and clean piece of software.
I think it would be useful to be able to specify these as
a factor of the default update period. eg 1/2 the
default period, 2x the default period.
I tend to set the times based on this anyway depending
on how often I want the feed to update. However, if I
wanted to have Feedreader running but not alerting me
so often to updates, I could then just change the
default period, say to 2 hours.