Agreed, a lot of what-ifs there. I’ve used VQ bolts in 6-7 different non-VQ receivers, including two OEM receivers and the brass receiver I machined from scratch, fired 1000s of rounds through them, and not a single handle ever hit the receivers, and not a single handle has ever flown off of the bolt.
I continue to use the VQ bolts because, as mentioned, I like the round, titanium firing pin design, the recoil spring design, the easily removed handle (needed because of the improved, in my view, recoil spring design), the smooth, hard surface treatment, the crisp extractor machining, and the overall precision of the bolt.
I can see if someone is used to the original bolt design, he or she might not want to mess with success, and I know the Kidd bolts work just fine, as I have used them, as well, but having used both, I prefer the VQ.
Now, I don’t like the VQ trigger group, since it looks like something from George Jetson's ray gun, and the performance is not there for the price. Here, the Kidd stands above all others. Both the Kidd and the VQ barrels are made from Walther Lothar blanks, so I could go either way there, as far as performance; the Kidd barrels look better to me but the VQs are easier to install -- I had nine kinds of hell trying to get a Kidd barrel into a stainless Tactical Innovations receiver. There is no way freezing the barrel and heating the receiver was going to work. I appreciate tight tolerances on both, but I think those tolerances tend to stack up, and the stainless receiver also wouldn't expand like one made of aluminum.
I would also use a Kidd receiver over a VQ, for aesthetics, mostly, and the Kidd is just cheaper with apparently equal precision.
Putting my money where my mouth is, I just made this stubby little beast using a TI receiver, VQ bolt, and Kidd trigger and barrel. The stubby walnut stock is a Green Mountain (still waiting on the Sparrow can: