First "sub-250g" build and first with DJI O3!

Hardware
Chose the 2Fiddy frame since the new version is built to fit the O3, doesn't require additional TPU mounts, and I like the aesthetics. Went with the T-Motor 45A AIO in the hopes that it's quality, and it has the MPU6500 gyro (in addition to the DJI plug). For motors, the 1804s are 1018mm³ in stator volume, which is just about spot on for a 3.5" quad. I'm running the Tracer RX since that's what I've been using for a few years on all my race quads. And Tattu 750mah 4S packs — they're the same weight as the 650 TAttu packs since apparently they're the same packs but with top-grade cells.

Software
Started with Supafly's 3-4" Freestyle preset, adjusted based on his online PID tune calculator. I then did some "basement tuning" with PIDToolbox to dial things in. I backed off the D and Master gains a little bit from the optimal to give a bit more headroom in case of bent props and such. Also adjusted some of the FF jitter/smoothing parameters, dynamic idle, turust linear, etc.

Video
I'm planning to use the O3 footage vs. running any HD camera (and that has largely the impetus for this build). 2.7k 4:3 @ 100Hz is what I'm running right now for minimum latency. This means final flight footage will be 50fps, which isn't ideal — I'd prefer 60fps for better compatability — but the 50fps video seems to play back fine on most displays I've tested with. I'm also using ND filters from Camera Butter, running manual exposure settings, and using the cinelog color and then grading in post.

GPS
I added the NewBeeDrone M10Q Micro GPS unit for more confidence flying over water, mountains, and other hard-to-reach areas. Updated to Betaflight 4.5 for the GPS Rescue improvements. Tuned the throttle values based on Blackbox data and set up failsafe to enable angle mode with slightly-above-hover-throttle in Stage 1. I haven't tested failsafe or rescue yet, but I'm getting good GPS lock and data. Note I had to drop down to 4K PID loop and DSHOT300 given the additional processing power that GPS requires (as per the 4.5 setup guide). I left one of the gyro lowpass filters enabled (slider to 2.0) to account for any aliasing with the 8K/4K setup. With 8K and DSHOT600, I was getting a very slow refresh on the OSD, indicating that the CPU was overloaded.

References
Build Video - https://www.youtube.com/watch?v=3kpWnWUvJDU&t=0s
Frame - https://ummagawd.com/collections/2fiddy-5-frame/products/copy-of-2fiddy-ultra-light-freestyle-frame?variant=39890616615006
Parts Bundle - https://ummagawd.com/products/copy-of-2fiddy-5-inch-build-bundle?variant=40644611768414

Reviews
https://www.reddit.com/r/Multicopter/comments/mn94hb/my_ummagawd_2fiddy_review/
https://www.youtube.com/watch?v=ngDT0B4Deek&t=0s
https://www.youtube.com/watch?v=-pJVi0Ou85M&t=0s
https://www.youtube.com/watch?v=7VNEUq1CZRg&t=0s

Flight Video
https://www.youtube.com/watch?v=FLbGahNwkqA&t=0s
https://www.youtube.com/watch?v=03wWn42surI&t=0s
https://www.youtube.com/watch?v=VKYuwalmFvE&t=0s

Nerdy Stuff
Ummagawd Tuning Video - https://www.youtube.com/watch?v=lLZ4U1I2R8k&t=0s
Rosser Motor Selection - https://www.youtube.com/watch?v=RXy00orSpfU&t=757s
Stator Volume Calculator - https://www.vitroidfpv.com/tools/motors