It can be somewhat overwhelming, but immigration is a "problem" that solves itself.
The part that gets me is reorganizing my labor force every time it happens, resulting in a half hour of wasted "U, C, P, L, Click click click click, Space..." repeated over and over.
But if you reassign enough of those immigrants to growing, and expand your farms, they'll feed themselves. Set up extra carpenter workshops and devote 5 of them to building newcomer beds. Recruit 5 unskilled miners and marvel at the stoneless livingquarters they make for you. Put brew drink on repeat. Then, once you've done the "immigrant scramble", you can work on integrating them into your REAL workforce.
Make good use of your founders and their likely very high skills in their specialties to stay ahead of the game. A legendary miner can tear through rock, forging a homestead for a moderate-population fort in a couple seasons at most, if he has nothing else to do. A high-skill carpenter will pump out more beds than you know what to do with. A long-time logger will keep a full crew of wood haulers busy all by himself.
My fort plans abuse my founders, using them, ironically, as the foundation of everything else. Sure, it may not be the glamor jobs, like working a magma forge, or decorating masterwork furniture with rare gems, but EVERYONE loves Trammeledpaddle's Dwarven Syrup Stew, and Oakgalleys makes the best dwarven rum this side of the Spine of Breaking. And it would take 10 of anyone else to keep up with them.