Since the machine is no more than 1200mm wide, then the stiffness of a UNP 160 beam should be more than enough.
If I were to change to RHS tubes instead, then I'm gonne sacrifice something else..

So if you think that you can bend a 1200mm long 160mm UNP beam, over a max length of 1000mm, then go ahead, I believe that deflection will be set at a minimum.

But then again, as I complete the design, I will have a friend of mine, do some stress and deflection calculations on it. :)