Back first - usual followed with top about 30 minutes later...just enough time for the HHG to set up a bit and allows easy cleanup. With the outside mold building method I use, the neck angle is set directly with the neck, so no overt advantage to top or back first, beyond the already mentioned glue removal. I seldom tweak bracing beyond some light scraper work once the box closes, preferring to selectively thin the top of the assembled box based on compliance testing, so no real advantage there for me. As mentioned, folks that set or fine tune neck angle by adjusting body shape (e.g., most building board methods, etc.) and those that either voice with the top on and back off, or fine tune in the same config, have excellent reasons to stick with getting the top on first.

So...if following a particular text or video building methodology, there is usually a reason for the order of build...and it's seldom based on the whim or fiat of the author. With enough in the way of building experience to understand when things can be changed up, departing from the order of build is a necessary step in optimizing the process for the individual - doing it prior to gaining insight as to why the author suggested a particular order is just an unnecessary complication.

Finally - unless the squeeze out is really bad, usually not a big deal to knock off the little bits of squeeze-out after closing the box - and if building in the Gibson canonical style, glue squeeze out is pretty much expected