both are only 5mm different in reach and plenty of standover on both
The top tube lengths are 1/2" different – thats nearer 13mm. But it's still not a lot, and the difference in standover height is much greater.
I've got shortish legs for my height (inside leg about 31") and there is very little standover clearance on my 16". An inch if that.
Unless you've got REALLY long legs you need a 16".