I'm thinking an 80mm stem would work best. But I will try both 80 and 100 to see.
I calculated an average cadence of about 85-95 in the videos. I think thats pretty good! I'll practice comfortably getting past 100. The cadence is very smooth thanks to the integrated spindle bottom bracket and feels nice and natural. I love being able to comfortably use different cadences depending on how I feel throughout my ride. I find myself not needing to shift much as I can easily push high gears at any cadence between 60-95 depending on my energy levels.