Coins looks nice, but I think 1.5 BTC is far too steep.....Anyway, gl with the auction!
Well based on previous prices 1.5 wouldn't be considered too steep. The problem is that MS-67 used to be something rare and exciting. Don't get me wrong, it still is really exciting but higher grades are become less rare and with the increase in higher grades more coins will be sent for grading with the anticipation of high grades this flooding the market with too many MS-67+ coins...
Well, that's just my theory anyway.
Good luck on the auction though. I'll be watching