In my experience startups have very little extra resources - you can't simply lay some documentation on them and expect it to "go to the right person". Why don't you pick up the phone and talk with them?
I agree completely with this. Additionally I wouldn't worry about the formality of the approach – if pinging them on Twitter is the best way to get the right person on the phone or out to a coffee - then ping them on the Twitter.
I think email is more possible to contact them. I don't have their contact number, and I live in a different country.