i don't know, the soft guard sounds ok, but you can experiment with them and see what works. i would start with a cheap one from wal*mart. if you live near mexico, i would get a night guard there at a dentist, as they are around $50 or so.
most all dentists want new x-rays. but, i recommend just getting one full jaw x-ray (panoramic) and it is good for 2 years unless you have some dental work (depending on what you have done) or have some pain or problem that requires more x-rays.