You can do them on any day; I wrote a bunch of stuff recently on this forum about this very subject as well as how we program them. How much one increases the TM has a lot to do with the individual so it impossible to say; as long as you progress in some manner and do so slowly, you will make great progress.
When you treat training like "testing" and try to lift as much weight as possible, as soon as possible, is when you take a huge training dump. So be smart, check out the posts on this forum regarding the Olympic movements. And as always, when you add something in, something has to come out. So adjust accordingly.