0. Read more
1. you have a 1024k rom on your chip, evox flashes the ENTIRE chip. Evox also resizes the bios when you goto flash it
2. you can use flashx to flash per bank, or use the x2 bios manager to make your .bin with multiple bios'
3. what ever you want, G is not required (if it was, then it would be the only bios....)
4. read the changelog and decide, no one can do it for you