The effect is the same, just it is the shield pushing against the fold bubble. I figured most combined field systems would have some form of countermeasure than allow a foreign 'fold' effect to pass through incase of such an event occurring. I suck at wording, so I'll try and tweak that. But for the no-fly zone thing would likely be double the size of the torpedo's 'blast' radius. So it'd be a decent 860 meters spread out. Against say a battleship for size comparisons it'd be close to the size of a Sharie, I'd compare against Nepland, or the Kuvies, but I can't seem to find measurements for them.
Yes, the warhead is the fold generator. As for it working in an anti-ftl field, which I don't know if it is a form of gravity generation, or some other exotic effect. But inside of a gravity well it is stated as being unstable and quite literally brute forced if possible for such a small FTL bubble. The damage could dip really low on starship-scale weapons, some medium ship main-guns or all the way up to its maximum damage. The no-fly thing would also vary wildly as well. I figured doing something like this would be an ideal balance and GM-crafting tool if they ever wanted to do such things. ^^;
But I'm perfectly content to wait and see what happens. Bear in mind Sya, I'm writing this before bed so it might be garbled. Lemme know on what to focus on if necessary.