Rule of thumb hold rod 45° release spool n lure should stop when it touches ground.
The tension knob controls take off the numbers control ending speed.

I run mine loose. Make a cast n loosen tension n hit a lower #
Cast n loosen till I get more than 2 loops of overrun .
Gain more distance n not as much force needed in cast.
Watch lure n stop line when it hits the water.
No I don't use my thumb to control the line during cast. Most do I don't.
It's whatever you feel good n can manage.
Kinda like not switching hands. I do n alot of the pros do.
Again whatever works for you. Take advice n modify it to your needs 👍

That’s a lot of votes for braid. Personally, I only use it on my light tackle striper rods and for casting flukes in the bushes for largemouth. 20 lb braid is excessive if you are fishing for bass or panfish. Too much to cover but one example is drop-shooting. Your want the lightest mono or fluorocarbon possible. A lot of guys use 6 or 8 lb. I use to fish with a guy at a local clear water reservoir. He insisted on using 17 lb nanofil. I stuck to my 10 or 12 lb co-polymer line and would typically out fish him 3 to 1. There are a lot of conditions to consider and then there is personal preference. I recommend trying a few different lines and decided what is best for you and your style of fishing. If you get into finesse fishing, you’ll take that braid off pronto.