Douglas fir's been pretty solid for me too, especially when kiln-dried. Still, I've had a few stubborn boards twist on me—guess that's just lumber being lumber, right? LVLs are great but yeah, the cost can sting a bit on smaller jobs. Sometimes it's just about picking through the stack carefully and accepting that wood has its quirks. Sounds like you're already doing all the right things though...hang in there!
Yeah, I've been there too—it's like no matter how carefully you pick, there's always that one sneaky board that decides to twist overnight. Douglas fir is usually decent stuff, but even kiln-dried lumber isn't foolproof. LVLs are awesome for straightness, but honestly, they're not always practical budget-wise, especially for smaller projects.
One trick I've found helpful is to frame walls quickly after sorting lumber—seems like the longer boards sit loose, the more they twist and warp. Still, even then, you'll get the occasional troublemaker. I've had to swap out studs right after framing more times than I care to admit.
Sounds like you're already doing everything you can, though. Lumber's just gonna lumber sometimes, and part of the job is rolling with those punches. Hang tough...it's all part of the fun, right?