My first edition bard archaeologist is going to do a lot of diplomacy checks in an upcoming game, and I'm trying to figure out how my luck powers can affect it. The reason I ask is because the diplomacy skill says you must talk for at least one minute (10 rounds) before you can make a check. So the big question: does the archaeologist's luck power trigger on the roll, burning 1 use? Or do I need to expend many uses, so that luck is on constantly during the entire 10 rounds?
I would say that it’s triggered on the roll, one round expense. As the ability says you’re calling on fortune favour to increase your chances of success. You’re not using the ability to say hypnotize the person to see things your way.
It's a swift action, so you could just bring it up in the check rolling round, maybe?
Nope, you'd need ro use it all 10 rounds.
Take Lingering Performance, then it only costs you 4 rounds of bardic performance.
Also the person who wrote the archetype expected people to take Lingering Performance and Fate's Favoured, so it's balanced around that.
If you are really going to be doing a lot of diplomacy take the feat signature skill for diplomacy. At 5 ranks cuts the time needed in half, at 10 ranks you can do it in a round by taking a -10 penalty on the roll, and at 15 you can make the check in a round with no penalty. So at 5 ranks it would take 2 rounds of performance with lingering performance.
Also make sure Heroism is one of your 2nd level spells at 4th level. It stacks with your luck bonus.