Good question @scaredycatguide you are correct. However I think that if you are too busy and feel that your SP will be better used by an active member then you can either delegate to someone you like for free (even open up a contest) or at a specific price per week or even to @minnosupport whih will be paying you specific amount weekly.
I do not think that you will earn curation reward if you delegate your steem out as it will belong to the person you delegated your SP to hence why you can agree on a weekly payment.