Impossible to know many active members are on CS, but searching for recent logins shows poor results in most locations (recent logins < 6 months/reply rate). BeWelcome.org has 200,000 members, and do a annual clean up, that turns profiles with onnon-functioning email address/ lack of logins to inactive in search. 200,000 means you are likely, when using the right approach (personalized messages, full profile) find a host in most locations. Of Couse, no paywall/ no ads/ no verification fee/ registered charity/ volunteer based are the bonus points.