2 · Message — use {first_name}, it's pulled from each profile automatically
If someone has no usable real name on their profile, the placeholder is dropped cleanly ("Hey !" becomes "Hey!"). You can also type a name override next to any person in the list — that wins.
3 · Pacing (protects your account)
Outside the send window the job pauses automatically and resumes on its own — even after a shutdown, an unfinished job picks back up when the tool relaunches.