I am making reservations this morning for our annual Good Friday crawfish boil by in La., a 25 year tradition. Also bringing the new son-in-law to get him a taste of our culture and food, crawfish, boudain, andouille, real gumbo, hope he doesn't become an ex-son-in-law!.
rodknocker has it right, resturants serve generally mild boiled crawfish but ask for a small sample first, I have seen people do that. Also as he said watch the vegetables as they do soak up the seasoning. At our boils usually the first two batches are for kids and women then they finally get right (hot and seasoned) from then on.
One key to good boiled crawfish is nice fresh crawfish, we get ours from a cousin who is in the business, kept wet and purged before boiling, a good burner that can keep up a boil and experience for just that right moment to get them out of the water.
BTW my family has never sucked crawfish heads! Never even heard of that until I went to LSU. We always made sure that we had plenty of tails so no need to suck a head!