I know how to use burrows, but unless you want to renew the burrows every 10 Minutes you have to deactivate the global alert. And once you did that your dwarfes will run outside. You cant define burrows for over 100 dwarfes and watch every time if the new migrants(childs got the right burrow etc. Also I like to change the labors of my dwarfes pretty often, cause most the time I get useless dwarfes like Soap Makers/Engraver as Migrants.
And if your dwarfes stay outside at least two will get killed by the next ambush or siege. This causes tantrums and your fortress is history.
Thats another problem, once one dwarf gets killed I loose my fortress during the folowing tantrum spiral. Its kinda strange, my dwarfes alls live in legendary bedrooms (8x1, engraved, statue, bed, chest, table, chair, armorstand, weaponrack) have tons of different food and at least 4 types of alcohol. All meeting halls (at least one dining room, one study room, one statue hall and one meeting area around 4 wells), stock piles etc are fully engraved, stone stairways and so on. On one map I was forced to produce nearly 50% of my furniture out of gold (I digged out some bedrooms and all I got was gold... why gold and no magnetite etc >.<"...) but I still lost my fortress to a tantrum.
The wiki says my fortress should be as luxury as possible to reduce the chance of a tantrum, but what if my fortress was to luxury? I mean my dwarfes live like kings (except my baron, who has a 10x10 bedroom) so they may get realy pissed if something happens what doesnt confirm with their snobbish charakter.
When do you start to engrave you walls? Do you think there is a maximum level of luxury for your fortress wich fires back if you overdo it?
Anyway, the tip with the lever - dangerroom was great, I got 5 axelords and 6 hammerlords within the first year (And also ~20 killed puppys/kittens and 4 killed babys). All 20 of my military dwarfes are at least proficient weaponusers, armorusers and dodgers. Now, in year 3, there was still no ambush, just one bronze golem and he is caged for "Fun purpose".