Sorry, I see now that your poll says, "starting hit points". In that case, I would be using choice #1: Max + Con Bonus.
I just started CotCT a couple sessions ago and if we hadn't gone this route, the fighter with 12 hit points (or took 11 points of damage in a single attack) would've been dead meat.
I tend to run pretty deadly games. I play the creatures intelligently, as appropriate for their Int score, but some players aren't ready for that. Because I tend to have tough combats, the PCs get Max+Con at first level, then 75%+Con at each succeeding level.
Calculating 75% is a bit of a pain when it doesn't work out cleanly on the die, though. For example, 75% of a d8 is 6 -- easy. But 75% of a d10 means taking 8 points one level and 7 points the next (averaging to 7.5).
I'm also leaning towards providing Max+Con if a PC should choose to take a level in a class they don't have yet (so no multiclassing penalty). But my players don't seem interested in that so far.
This means I need to bump up other creatures, too. I typically give them Max+Con at first level and then 50%+Con at succeeding levels. So the beasties last a bit longer at 1st level, but the advantage goes away at higher levels. That's because at higher levels I typically use more intelligent bad guys, so the focus changes from brute force to tactics.
I have a Perl script that I can type in a dice string (like "3d8+3") and it'll figure out what the hp should be for either a PC or non-PC.