iMac 27" Mid 2010 RAM Upgrade
The answer is 'Yes, it will take them.' 8GB sticks were 'unsupported' at that time, but just turned out they worked.

I have an old Mac Pro that has the same 'unofficial' double-storage. Shoudld take 32GB 8x4, does in fact take 64GB, 8x8.

It's only the 21" iMac from that series that really can only take 16GB

Ref - Everymac &amp; personal experience.

For specifically which sticks it will take, OWC doesn't ship here so I've never tested their algorithms. I would use Crucial's detector tool, which has never let me down.