Am I on the right track?

[Boomer]

I also have had difficulty finding much comparison between the NX-250 and NX-150. I read much about the 250. Is it just that people find the roominess for the 5oz worth it?

Depends on how wide your shoulders are. First of all, have you tried a Clark? From what I've read & seen, they're rather big & heavy as compared to some of the other options available.

For 3 season camping, make sure that you get a 20* UQ.