It makes sense that the gaps in the reed plates are not uniform. The larger lower notes are going to be vibrating at a slower rate to the point they may even whip around a little so they would need a wider gap so as not to contact the edge of the plate.
I haven’t snapped a reed yet gapping but I have bent the tongue up so far the reed would no longer sound and once also caught my shim on the end of the tongue when trying to slip it under and crunched it up like an aluminum can(a very sad day)
Blowing really hard will flatten a reed. In fact I’ve used this technique for tuning. If I’ve worked on a reed and find when I put the cover back on that it’s still just a hair sharp I will overblow very loudly on that one note and it will usually bring the frequency of that reed down into pitch.