I got the best drawer guides I could find: they are equiped with 2 sets of 3 metal balls, each set is spaced at app. 4 cm. It's the better kind of drawer guides I could find.
I tested them before and they really have *no* unwanted movements up/down or left/right. Maximum bearing is 10Kg, that will be enough.
There's no target for overall weight, I will see, or better: feel, when the camera is finished.
I was very active on B.com and before on offthedeck some years ago. That's where I know you from :-)