I want to change out the X and maybe the Y to linear rails. I'm using IGUS's webpage http://www.igus.com/wpck/16474/DryLin_T_Miniaturfuehrung because you can get cadfiles in the dimensions you want... make it easy to mock up. However I don't know squat about rails. would a single 12mm rail be enough spanned across the X axis? do they need a solid thing to mount to the full length? or are they strong enough to hold the weight themselves if its spanned?