Old Panasonic Lumix, an old iphone, GoPro...30FPS is ok. 60 is better.

Trying to see anything on a cellphone screen is useless. The trick is to get in onto a screen where you can see what is happening. Like 30" diagonal. And be able to play it back frame by frame.

A 3/4 view including the tree and the front suspension has been most useful for me. Count the frames from the one where the rear first moves to the one where the bottom bulb goes out, and compare run to run.