Shadow Handle strength extended

Quick question,

I’ve always been a big proponent of the Shadow Handle set from Nimbus. I love them. But I’ve always had both of my handles (or stub) pushed all the way into the base.

My question is, how far out can you slide the handle bar before running into issues? I don’t want to do this on my front handle bar, rather my T in the rear that I’m mounting a rack on. I can make the current length pushed all the way in work, but would love another inch or two.