I am testing a Genius 910 and I am 6'2" tall, 32" inseam, and long arms. I was able to get a LG to fit me very well with a 100mm stem and the smaller bike feels very good overall. I also could have ridden an XL, but that would have been with the 80mm stocker stem. Different vibe…subtle, but different.
I like the way a longer stem weights the front end of a slacker trail bike but I am not riding this in AM territory.
As far as your leg length, I am not sure when you would get too much seat post out of the LG frame. That I cannot help with. We seem to be a different proportion.
PS: I am typically an XL in something like a Stumpy FS (with a short stem like 90mm) and even in the Scott Spark 910 I was an XL, so fitting on a LG Genius was a bit of a revelation.