Pigdog- that sounds like bloody hard work! I do agree with cutting bits off with the angle grinder first as it does make certain bits easier. The spot welds holding the ute quarters on are very "soft" for want of a better term welds. As long as you've even half centred the hole they let go. A few of the welds connecting the tail light panel and the quarter even let go with a good firm yank.
Anyone know where you can get spot weld bits sharpened? You can buy a sharpener on Ebay for about $2500!! The bits are too expensive to just use once.