I'm of the opinion that you shouldn't present a choir until they're absolutely ready, so if the choir in general is ready, then maybe the people that aren't ready will have to sit out. If EVERYONE isn't ready, then they just won't sing. I don't believe in throwing anything out to God. People say isn't not the presentation, but your heart, which I agree with, but if your heart is in the right place, you'll WANT to get better, in other words, you'll practice to perfect the songs. Any mindset less than that tells me that the person doesn't really want to sing.