2 minutes is a minimum does to see change.
Yes, use the recommendations within an episode on the amount of time to spend on an area as a guide. Some episodes have 1 focus some have multiple areas that are addressed.

Yes, you are fine using an inner tube to start with. In time you may need more at that point you can purchase a band if needed. Frequency is based on your situation and what you are addressing. Are you seeing change? Does the area still need attention. The number of wraps, timing, etc is going to depend on the person and how tight the band is wrapped.

Here are 2 that address the trunk which may be an impacting factor with downstream tightness restrictions
Jill Miller Smashes Your Guts! (and psoas, and tacked down viscera, and matted down abdominals…) Part 2
Jill Miller Diaphragm Evolution Part 3: Eccentric Loading
Episode 301: Psoas Flossing and Biker Hips
Episode 129: The Twin Bowstrings, the Psoas and Scalenes
Episode 75: Your Inside Psoas Bits, World Record?
Episode 26: Hips and Seppuku: Psoas and Hip Soft Tissue Mob