I think the Breakaway, properly installed is a good product, though too expensive for me. The good thing about this product is that it releases with the front brake. I think you would just need to tap the front brake lever to quickly release the lock, and deceleration will occur. For $17.95 I would buy it. Not 179.95. But it might be worth the price for safety.
I have used the Go Cruise throttle control, similar to this one on a motorcycle and my Swing: https://www.walmart.com/ip/2wheelride-Go-Cruise-Throttle-Control-7-8in-Handlebars-GC22BK-Easy-to-install-no-tools-required-By-2Wheel-Ride-From-USA/740233076?wmlspartner=wlpa&selectedSellerId=14995&adid=22222222227126615170&wl0=&wl1=g&wl2=c&wl3=235418536014&wl4=pla-387856177125&wl5=9006635&wl6=&wl7=&wl8=&wl9=pla&wl10=118772551&wl11=online&wl12=740233076&wl13=&veh=sem
I have also used a $40 Vista Cruise Universal with thumb lock and release, which works as well as Dale's less expensive Vista Cruise Throttle Clamp.
But, Dale, I think I would prefer the Vista Cruise clamp that you refer to. If you can adjust the friction in the locking position, it's better than my Go Cruise. Here's why: With mine, if I want to slow down in the locked position, when I want to afterward go faster, I have to reset the lock for a faster speed every time. With yours, you can lower and raise the speed on-the-go, and not have to reset the lock with a thumb or finger because it maintains friction BOTH WAYS. While my Go Cruise is the simplest to install, yours is almost as easy, with the addition of adjusting speed without resetting the lock.
Also relating to throttle locks, I have used them on both motorcycles and the Swing. I don't know how many Swing riders appreciate the advantage of a throttle lock on a Swing vs on a shifting motorcycle. On a motorcycle, if you are cruising along and locked in to a certain speed and reach a hill, Your engine starts "lugging," and you too often need to break your throttle lock and reset it more for hills; whereas, the Swing's CVT transmission never "luggs," and adjusts automatically with higher RPMs on hills, keeping your speed up a little better than the single locked gear of a motorcycle, thus fewer adjustments to make.
On flat highways as in some mid-western states of USA, you won't notice the difference between clutch motorcycle and Swing, but enter hill country, and you can still have the throttle lock work for you more effectively on the Swing.