I've been looking at different gantry arrangements that I can build using the material that I already have.

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From left to right they are:

A: 3 off 40x80
B: 2 off 80x80, 1 off 40x40
C: 2 off 80x80 with 40x40 or 40x80 bracing
D: 1 off 40x160, 1 off 40x80 'L' arrangement
E: 1 off 40x160, 1 off 40x80 'L' arrangement with lower linear rail front mounted
F: 1 off 40x160, 1 off 40x80 'L' arrangement with greater gantry clearance
G: 1 off 40x160, 1 off 40x80 'T' arrangement

My original arrangement was 2 off 80x80, one above the other without any bracing. On the feedback I've had so far I think that any of these new arrangements should outperform my original. I like A, B and C as they allow the ballscrew to sit in the gap but I know that strength and stiffness are more important. D offers good spacing between the two linear rails but I think that it may be a step too far as it limits the material thickness too much. E is my current favourite. The only thing I don't like is that the Z axis will protrude out further from the gantry but I think I can live with it.

Of these arrangements which do you think offers the best performance?