Nyet. Joints increase the weight by quite a bit. They may seem
lightweight, but really, they all add up.
And the problem is that when you increase the outer diameters, the
joints no longer fit exactly. It's a bit hard to explain... but
suffice to say that the parts meet each other at curved surfaces.
So when you increase the diameter of one member, you must account
for it exactly in another member which is attached to it. It's a
delicate balancing act.
And you know how bloody unreliable Solidworks can be - it can give
you all sorts of imaginary problems when there are actually none at
all. 
