Muertelis

I bought recently DJI Osmo Nano. That is one of few first flights. It's mounted on 5 inch quadmula frame. https://youtu.be/kXDwHNnyC7s?si=v4Sa4oqpieRNlF3d.

I like it :)

Hi, sure these motors can be used for 3,5 inch. For example Crux 35 uses motors 1404 and 3500 kv on 4S and it's waaaaay below 250, and it's 3,5 inch :)

:)

you can always save tune profile you already have and apply anohter one that you're tunning. That is great experience to tune it by yourself - no matter if you use basement tunning or any other. Seeing what change does to your flight if you increase P or I or D is amazing. :)

For future builds - it would be better and cheaper if you learn to tune it and than tune it yourself using PIDToolbox or Blackbox log explorer. Or both :)

You can find a lots of tutorials on YT - Bardwell or Chris Rosser, or UAV Tech, or PIDToolbox Guy. For me PIDToolbox Guy and Bardwell are the most I undrestand. But all of these 4 guys are amazing and it's worth learning from them.

Great method is a Basement tunning (by PIDToolbox Guy)

use E6000 glue. It's perfect for this kind of applications. I use it on all my drones - tiny whoops and 5 inchers.