IMO, it's good for a fidgety horse to stand tied for a long time. I'd prefer to tie to a hitching rail, at or above wither height, tied to baling twine. I have also heard success stories with the Aussie tie rings, but haven't personally tried them. Seems to remove a lot of anxiety with the actual being tied, but that doesn't sound like your problem. If a horse is fidgety while tied, I'll get him out first, tie him up, and then go about my business working other horses and doing chores and keep an eye on him, but let him stand tied there for a while. If he moves while you're grooming, move him right back to where you had him. If he takes a step forward, make him take a step back. Horses can stand tied for many hours, the experienced ones cock a leg and fall asleep, the fidgety ones learn that fidgeting wont get them anywhere, and they may as well do the same, cock a leg and fall asleep.
I completely agree with Tessa.Untying a horse and taking them out or something is the fastest way to teach them *not* to stand quietly while tied. In fact, it'll teach them that every time they move around they get untied and do something else. It's enabling the wrong thing, not the right thing, which is to stand nicely while tied up.
I will go out and randomly tie up my horses for whatever periods of time. 5 minutes or over an hour. They will stay there longer if they are pawing or doing something other than falling asleep. I can find lots of things in and around my barn that need to get done. So that's when they will get tied up.
Aussie Blocker rings do work. I had this mare that tied fine for years, then all of the sudden decided to through a fit and yank back, breaking the lead snap. She realized what she did to get loose, and then stared setting back *every* time tied. I got 3 Blocker rings for use in the trailers, barn, etc. She couldn't figure out why she was still tied when she jerked back now. So she quit. And then would purposely try to scare her while tied with the Blockers and she's set back and pull, but she never ended up pulling the rope all the way through. Eventually I could ride by with the four-wheeler fast and she'd just stand there....
I used cross ties a couple of times. I didn't really like it. My horse couldn't look around very comfortably. Not mover her feet, just bend her neck. So we just tie with a single lead, like I've always done.