Short answer: see if you can find the geometry charts for the clockwork and compare with the cotic.
Long answer:
I’m 5’11” (and a half) on a medium.
I’m often on the line between medium and large frames. I had previously been riding a large Spesh Carve and loved the reach but found, despite long limbs, the standover wasn’t very confidence inspiring.
I guess my mtb old school mindset played a part as I have seen many that are not bothered by this so much these days.
My Carve had a 70mm stem and 700mm bars.
I spoke with Paul at cotic who recommended a medium, which was only slightly shorter but had more standover. I run it with a 60mm stem and 740mm bars.
The standover was just what I was looking for. Ideally I’d have a tad more reach, maybe 10mm but then I mainly ride road bikes so am used to being stretched out. I could swap for a 70mm stem but love the way it handles right now.
A friend of mine that is 6’1″ but likea quite a small bike has ridden mine and thinks it’s perfect so I guess it depends what you usually prefer.
My only issue has been getting a saddle that feels right. I think it may be down to the seat tube angle possibly. I really can’t be sure. I’ve tried at least 5 different saddles and a couple of those were my ‘go to’ default ones. None seem ‘just right’ but it hasn’t stopped me enjoying the bike.