L Style Gantry on a 6040 sized machine?

[Sterob]

Have sent emails to UK and China enquiring about 45 series extrusion...no good leads yet.
In the mean time, it seems that some supplies do not offer an intemediate size, ie 90 x 135mm.
This means I have to use a different sizes for the Gantry.
I was wondering if there is a difference in the stiffness of a Gantry between these 2 options?
Steve


Option B is my preference, if joining on the back is acceptable to do.