Treadmill desk (arms often rest on desk), Foot Pod or Calibration?

I often just fast-walk versus running, and do this while doing other things on the computer (I have a treadmill desk). This means my hands are not moving much or swinging at my sides.

What would be the best way to get stats as accurate as possible for this scenario?

I see that I can calibrate the watch to the distance the treadmill shows at the end of my workout but is that good enough? I assume I'll have to calibrate it EVERY TIME since the amount of time my hands are on the desk vs at my side are going to differ each time (if I'm watching videos vs typing emails)

The Foot Pod sounds like it might be a good option and it's not that expensive. Am I just better off with the foot pod?  I'm not an athlete but I do like to record my basic stats like distance. Speed would be nice too so that's why I may be leaning towards the foot pod if it records speed.