Make no mistake: when you have a shaved head, you need something to cover it up in the sun. That's why I got these. Because I have a big head, I wanted bigger hankies, because they're easier to tie on and get full coverage with. That's why I got the jumbo size.
When it comes to hankies, I'll tell you from extensive experience that you're better off with slightly higher quality and all-cotton construction. The cotton is softer on your skin, doesn't warp or shrink in the wash, and seems to hold its colors better than cotton-poly blends.
These hankies are HUGE compared to the 22-inch ones you're probably used to using. You wouldn't think that extra five inches would make such a difference, but it really really does. It's easier to tie it around your head when you're working with that much extra fabric. Think of it this way: if you're folding your normal-sized (22 inch square) hankie into a big triangle, you're getting (according to the pythagorean theorem) about 31 inches of play to work with in tying the hankie around your head. You wouldn't think it, but your head can be pretty big around! Mine is 23-24 inches around, roughly speaking. 31 inches is not that much to work with when trying to tie a knot behind your own head for a snug fit. Now, a 27-inch bandana, on the other hand, gives you 38 inches to work with. That 7 inches of additional length makes a big difference.
In short, if you like bandanas to wrap around your head to protect it from the sun, this is the best option. Not the cheapest, but definitely worth it. Get sunburned on your head once and you'll agree that it's worth it to have adequate dome coverage.