Why limit yourself to one source("Twitter? Telegram?")?
You can simply join all various bounty programs, only signature, and sometimes telegram requiring profile picture/name, is limited.
It's up to you how much time you'll want to spend for bounties, surely alot of the projects suck, but you could atleast join their Telegram, no reason not to

When it comes to Twitter and Facebook and other social media bounties, they generally are the ones that take a bit of time, and also requires reporting it on time,
so it could easily get out of hand unless you're organized!
For finding what project to dedicate most of your resources to (signature and such), it's only a matter of researching the project, considering how much the bounty allocation is, and how much the signature program allocation is.
I wrote a guide about analysing ICOs which you might find helpful:
https://bitcointalk.org/index.php?topic=3752728