OK, so I finally broke down and decided to get the 8x10, and now I need to find some lenses. I would prefer lenses with 11x14 coverage, as I would like the extra movement and less light falloff, but am wondering if this is necessary. From those of you more knowledgable in this area, I have a few questions:

1) What lenses are best/should I avoid?
2) How much movement does an "average" (say 450mm) lens allow for (ie, is it worth the extra $/searching to find 11x14 lenses, and will there be much difference)?
3) I've read that newer 8x10 and larger lenses are of lower quality than older lenses because of less demand for such lenses, and they remain "softer" than older lenses. True/false?
4) Is it difficult to mount barrel lenses w/shutter (ie, worth the time, effort)?
5) What is your preference in lens focal lengths (ie, your 2 favorite)?

Thanks in advance for all your help!