I am 5'9", 195lbs, 29" (and found out later I have more torso then others my height). I had purchased a 24" inch frame based on their reccomendation, and it worked great but I was not getting the lift I wanted while under load. I traded a member on here for a 26" frame and have been very happy with it
Measure your torso length. It'll make it easier when you speak to Kifaru. If you dont know how to, look it up on YouTube, or look for an article with pictures, it's easier to understand that way.
5,7. I have both the 26 and 24. The amount of shit you pack I feel has more to do with the sizing then your size.
That said I prefer the 24 for backpacking when I am going thru busy crap. The 26 is good for having taller loads.
Depends on your use. I have a 24", but I use it for hunting, as well as military ops and backpacking, so I didn't want the extra height of the 26". 24 gives me enough lift, but not too much height. Maybe 2" wouldn't make that much of a difference, but I like the 24. I'm 5'9" and about 195
If you have a 34" inseam at 5'10" tall, get a 24 inch frame. You are all legs. That's going to put you in the 19 inch torso range. No matter the load, you'll have all the lifting angle you will need with a 24 inch frame.