The Weiss Walkie is based on a leash trick that most older dog trainers have used for decades. It's easy to do it with a regular six foot leash. No special purchase required.
With the leash attached to a collar, run it down the dog's back. You can go to just behind the front legs or a little further back (but assuming it's a male dog keep it in front of the *****). Holding the portion of the leash laying along the dog's back in place, take the loose end and loop it under the dog, up the other side and under the part of the leash you're holding on the dog's back. Instant Weiss Walkie.
I don't like Halti's and Gentle Leaders. Too many people use them incorrectly. I've seen way too many dogs' heads jerked around roughly when they hit the end of the leash. And no offense to your friend, but since he seems to think a "choke" collar is a no-pull collar (it isn't, it's a training collar) then I would be wary of his ability to use a head halter correctly.
Another option may be a prong collar. They look like torture devices but they're much less likely to hurt a dog than some of the other no pull devices. They're pretty much idiot proof.