John's Alu Profile build

[Evengravy]

There's nothing wrong with rails on the rear plate, I've built dozens of machines using both methods and neither is better than the other because the difference between them is hardly anything and any advantage one as over the other is mostly dependant on machine design and user needs.
In your case with a short Z-axis, it's the best method because it allows you to make the most out of a short-stroke while allowing you to keep the gantry low and squat giving the best strength.

Don't worry about the profile it will be fine.

Ah that's good to hear, I didn't go for the L design you have no, I wish I had of kicked around here before but that does look like a better solution than mine, unfortunately I'm quite a way through the build so at this point I'm just looking to get her done and running. I don't know if you would have any comments on the design as it stands? There's a few places I could reinforce around the gantry connection to the Y axis plates etc. I'm sure I can figure something out there.

I could always beef up the gantry with some steel plate on the back-side too, if that would help. I might just get the base/table done next and see how she does though.