I haven't had anyone try to get kicked after the first two bosses yet but they should divide both tome rewards equally between all three bosses in my opinion. If you want the last boss to be extra significant then make it so you only get body drops (and maybe legs) from them and leave it at that. If you put all the tomes into the last boss we will just have another problem with people playing the CT withdraw game until they get an in process run.

As for the speed run issue, Brayflox HM is getting a bit silly now, people are trying to make it 3-4 pulls for the whole dungeon. Missing out the chests is annoying to me as well as I'm trying to gear up secondary jobs and the darklight is useful. Not only that but SE did seem to put an anti speed run mechanic in to Brayflox anyway with the Glider mobs, they seem to have random aggro so if the tank pulls 27 of them at once they will attack me on BLM even if I don't have hate at all on them. The tank might be able to take the pain but I can't on BLM and I find that's what's causing most of my wipes in Brayflox, the healer ends up having to heal me and the tank and it's too much, I can't even help out by reducing enmity as I didn't have hate in the first place.