Both of these things are surprisingly difficult to do properly, with enough consistency and control. I believe temperature profile can noticeably affect the roast, and being able to consistently hit a profile (and thus experiment and improve) is really difficult with something like a heat gun.
I did the heat gun thing for a while, and the air popper thing for a while, and even modified the air popper to be able to control fan speed and heating element separately. I got good results but hit a wall and needed more control. I started building an Arduino-controlled air popper to be able to get more consistent results, then decided brewing top-quality coffee coffee was challenging enough when roast quality was delegated to experts. Since then, I've been buying from local roasters.