Feng, you are correct in your assumption.
Less water is better because bettas tend to get more disoriented with more water while traveling with all the bumps and turns and what not. It also makes them not have to put much effort into finding their way to take a breath of water. - I always ship in about 2.5" that end up being about 3.5-4" tall, I fill it up so that it'll cover the betta's back when the bag is on it's side. It's what has worked best for me out of all the ways I have tried.
As long as you fast for a couple days, double dose with prime, and give them 1/3-1/2 water to 2/3 -1/2 air(ish) then you'll be in good shape.
Anyways, I came here because I was wondering why people are bidding so hard on this guy?
he is a good looker, but $70.00 for him? I just don't see it. There are plenty of other similar fish out there to bid on and probably with better finnage
IF I liked solids, I'd definitely bid on this guy though, he's nearly perfect besides some ray extension on the anal and a very slight spoonhead
And this boy..oh this boy <3! I could see this guy going for $70!
Poor boy!! Look at all that dragonscaling on his eye :( If I had seen him last week, he'd have been on this shipment to me.