I currently have the 12" VZ58 pistol with a fixed SB SOB brace on it on the buffer tube attachment.
In the past, I've looked at some of the folding knuckles and things that would fit the buffer tube - I even tried one of the cheaper UTA ones that ended up being HORRIBLE. But I realized that with SIG Sauer making their MCX Rattler upper conversion kit, they made a Buffer Tube Delete with the 1913 rail on the end. However, the way it screws onto the lower, I don't think it will work with the VZ buffer tube adapter since you'd have to be able to screw it in from the inside of the AR lower. However, I saw that KNS Precision then began making their own (
https://www.knsprecisioninc.com/product/ar-mcx-stock-adapter-without-flange/) and it looks like it WOULD work, as it screws into the buffer tube area from the railed side of the adapter.
Then, either SB Tactical's or SIG's thin folding brace could easily be attached to the VZ. While I've enjoyed the SB tactical braces in the past, I think I'm leaning toward SIG's brace for look. Wish I could find a store with both in stock to look at, but no stores around here bother to stock these braces. Regardless, I do believe this will be my little upgrade to my VZ58.