How to change focus duration options ?

Right now, I can either choose 1 hour or until tomorrow morning (is that 7 am??). I'd like to set it to a custom time. Today 90 minutes, tomorrow 2 hours, sometime next week probably 47 minutes, etc. etc. 1 hour is too short, and overnight is way way too long. Or better still, how to set it until 10:00 pm tonight? (not recurring, just tonight). Tomorrow night it'll be another time. 9:30 pm maybe?

thank you.