If you look at the Roulette, when you select one there is a bonus you get. Big bonus you get is only once a day, but you will still get the rest of what they say on there after you've run that specific roulette. I think it is mostly just money at that point though. There are 6 roulettes now I think, Low, High, Expert, Guildheist, Trial and I feel like I'm missing one other. Anyway, if you want the full bonus, you basically run one of each. The amount of tomes they reward do vary, but you should get some from each. You can run them again, but they won't give you the same bonus.

It is totally possible to get 800 in a single day, when I doing myth grinds for my Animus books I would do 1500 myth in a single day easy and 3000 over the course of the weekend/week. But when you hit that point you're just getting the base tomes the dungeon itself rewards. The reason there is a limit on soldiery tomes is because the gear you get from soldiery is the current highest level gear you can get without going into Second Coil. So they don't want you to immediately have the best gear the first week, people would do it. So they cap it so that you have to work towards it over the weeks. I've been getting cap on soldiery every week since 2.2 was released and I just finished getting all of my soldiery gear and il99 average. I still have another whole patch before they release a new tomestone, so I'll be gearing up another job in the next 3 months.