Thanks for the comments, JPTS.
I've played 2 very large MTTs ($2500 entry, multi-day,2-hr levels). And was out before the 5th level in each. In the 1st (Rio,
wsop), I played poorly down to less than half my starting stack. I shoved A-10 when I flopped TP-TK and the pre-flop raiser checked. (With 3 players, I had about 1 1/2x the pot left.) PFR had caught a small set.
In the 2nd (Venetian), I had a couple tough beats. My KK lost to a JJ7-flop when out of pos. Later, I shoved AA on the turn when a very loose, uber-aggressive player had caught his small inside-straight, after calling my 2 raises. In both those
hands, things went as I'd hoped -- my Pre flop raise narrowed it down to 3 players, including a specific villain I was targeting in each. In the 2nd,I was sure that the only hand that could bear me was 74 that called 2 raises. (I was right!)
If anything, I think I played aggressively too early in those tourneys. In smaller ones, I've often failed to take stack size into account.
I have played 1/2 for 6-7 hrs easily many times, and 10-12 hrs a few times. but focus can be an issue after e while.
One concern is keeping track of pot size, and sometimes stack size with the larger starting stacks, since I'm not used to that. I'm also concerned about playing against a higher caliber of players than in used to.
More thoughts appreciated.