Go to this in GS in IDA, literally change the 90 to 99, done and done. This is the casting cap and overcast result setting. If you wanted your casting to be limited to say -70, you could just change the top number to 70 and then the bottom number to whatever you want the CT to be when they go over that number.
If you ask me how to use IDA or Hex Editor to actually edit these and don't bother to even try then don't bother asking me. Anyone with a brain knows how to search for this function and press F5 then go to that address. Its not some complex thing.