Askel

I think your getting a little too hung up on the numbers. If you're ordering a frame without the chance to ride it, they're sort of helpful sometimes. But in this instance- where you can test ride all the bikes, I don't think it's as important as you might think.

For starters, we don't know what kind of terrain you'll be riding. The geometry of most mountain bikes is always a compromise in some direction towards uphill or downhill or rough or smooth or whathaveyou- nothing will be perfect all the time. That's why I have two mountain bikes, and am always looking for more.

Test ride lots of them- preferably in similar conditions to what you'll usually ride. If you have to add a oddly sized stem or seatpost or something, it could be an alarm that it might be the wrong size for you- but not always.

Keep in mind the mountain biking is a very technical sport- as you learn better technical skills, how you ride and position yourself on your bike will change over time.