whew finally read it all, sorry I'm kinda sleepy so it seemed like a lot.
Ok..
1. Welcome to ecomodder! yeah its a great site, I'm a fan
2. I don't have either of those tires and not sure what i can offer, but I would say try searching (Google) for LRR data I know its hard but there is some out there (I heard out here in California it is supposed to be avail. for tires sold after July '08 so soon right(if thats the case I will post whatever I can this summer)
2a. Get one that's rated LRR, weighs the least and can be inflated the most, I personally think weight is most important
3. your on the right track with skinner tires
again welcome; glad you joined up Derek!