Just an update.

I mounted up the 25 degree stem last night, but it sure seems steeper than claimed. Anyway, it's 100mm like the original but the handlebar is about 1" higher now. I rode it this morning and immediately noticed that the seat needed to slide back now.

After my ride, I moved the seat back a bit and adjusted the angle on the bars a few degrees. I'll give it another go tomorrow morning.

My hands still got a bit numb, which is still indicating gloves would be useful.