Re: Semi De-Wanging the Wanging Bar: Edge Pro Edition
Do you want the bridge to function more or less normally otherwise, and just not go out of tune when a string breaks?
The easiest wat to do this is to either fully block the bridge, or use a Tremol-no to lock it down. This will keep the guitar in tune when strings break, but will mean it's going to function like a fixed bridge, so you can't do anything with the bar.
Next would be to block it for dive-only operation. You can either carefully block it so the trem only moves in one direction, or use a Tremol-no with the Deep-C in position (and I'd lock it down with an allen screw rather than a thumbscrew). This will let you dive, but won't let you flutter, use bar vibrato (unless you carefully do down-only vibrato), or pull back on the bar.
I haven't used a Backstop or Black Box, but maybe a decade ago I had a Tremsetter in a 7620 for a while. I honestly don't remember if it had enough counterforce to keep a guitar in tune when you broke a string; I suspect it'd at least stay pretty close on the high e string, but not on the wound strings. It worked relatively well - it'd let you do in-tune compound bends, and pull up as well as dive, but you could feel it in the bar which was a little disconcerting, and it absolutely killed flutter, if that's important too you.
If it's just a matter of not wanting to chance a break during a particular performance or something, and you don't really need the bar but want to have the option of getting at it, a Tremol-no is a pretty good compromise. Most of my Floyd-equipped guitars have one, and the rest will as well, once I get around to ordering and installing the last few. I usually just leave them unlocked, but it's useful enough to be able to quickly disable your trem that I like having the option there.