Well to begin with you can't mix together the makers of paint - their terms and conditions and places of employment will not match.
Secondly you do not say the make of the paints involved
The phrase - Matt- Matt Silk - Silk not cross mixing - lacks clarity.
The size of the container is immaterial
You do not say what you intend to apply the paint to.
I suggest you go ahead with your plan and see what happens - and then you will be the world expert - after all - what harm can it do? What might it cost you?
You will never know until you try - go on - live a little.
Take the risk..., January 2015