Major disaster - need advice

[glenn]

If you do the 'drill out' option, bolt a 1/2" plate down with a 2 MM or so hole centered on the bad bolt.  This will keep the drill bit from walking.  Next a 3 MM, next a 4 MM, etc,    Hand file if it's off center a little.  Last drill is the bit for a 6 MM tap.  Then tap it out.  These bolts don't have much loading -hopefully.

[glenn]

TIG???   Thousands In Gold???