A couple other thoughts -
I prefer podcasts over webcasts because I have to drive a lot for work. If you do make a webcast, you may want to consider also having an Audio-Only download for it.
I typically listen to 4-5 hours of podcasts a week. I'll add a couple to you list, and you can find some more here -
http://www.itunescharts.net/us/charts/podcasts/2017/07/06
Tim Ferris Podcast https://itunes.apple.com/us/podcast/the-tim-ferriss-show/id863897795?mt=2&ign-mpt=uo%3D8
While I don't always like his delivery, he gets such good guests on that it makes for a great listen. But, he also does quite a bit with no guests, too. So you can learn from him in both ways.
The James Altucher Show - https://itunes.apple.com/us/podcast/the-james-altucher-show/id794030859?mt=2
He's another guy who lost a ton of money and earned it back. He's very vulnerable in his podcasts and writings which makes for a good read.
Also, I recommend this one - Bitcoin & Markets - http://bitcoinandmarkets.com/ This guy just gives his take on things. No other people on it. He knows his stuff and gets fired up as he's discussing Bitcoin. I find it impressive that he keeps going, and I'm glad he does. I've learned from his content.
One of the key things is consistency of content. Talking seems easy, but staying on point and providing a good message each show may be difficult. If you're going to start, consider that you'll need to give it 6 months before you get comfortable in front of a mic and 6 more to get in a groove.
Good luck
You can a list of top pd