If it's a 3pm meeting and you're flying out of BOS, I would take the Monday AM flight. Assuming the meeting is in the US, there wouldn't be an issue of losing time to time zone changes, you could only stay even or gain, so without even looking at any schedules, I'd think you could even be on the west coast by 3pm without having to leave too early--although, Logan being Logan, weather will come into play at certain times of the year (I'm sure you've had the experience of Logan being "fogged in" on a nice sunny day in inland greater Boston.).

If your client is more budget-sensitive than time-sensitive, you may be encouraged not to come in Sunday nights, even if it means risking missing Monday meetings. When I started my current project, I flew in Sunday evenings to be there for Monday morning, and was asked to switch to Monday morning flights to save the extra hotel night.