If you really want to do prime runs, send PM to lb runners. Be polite, do not spam, just ask for letter runs ONCE each hour or two and wait.

Be a bit smart about it:

If someone does not answer you in 10 sec, no it is not because they hate you. They still do not hate you if they never answer. Perhaps they never saw your tell.

A warrior probably does not usually want 2 warriors in the party.

A rogue might be ok with 4 rogues.

A ds mage is useful.

Etc. etc.

Play a game: See how many of those lb'ers send you a friend request.

The opposite is also true: Be rude, spam them, scam them, be a terrible player and you might end up on people's ignore list.