MakerBot Print is our newest print-prepration software, which supports native CAD files and STL assemblies,
allows you to interact with all your printers via the Cloud, and many other exciting new features.
It's A good point around the built in spacers but the reason I didn't design them into the model was because it would have made printing them a nightmare. The blocks and pulley supports are designed to be printed upside down and so each of their top surfaces are designed to fit flat on the build plate. If I model the spacer like in the corner pulley supports, you'd need a support building across the entire surface of the model, to the height of the spacer. It didn't matter with the corner pulley support as these need to printed on their sides. The pulley supports have the built in spacers on the underside as this didn't affect the printing so you only need the spacer washer sitting on the gantry blocks top surfaces.
The length of the blocks is larger than the stock ones but the print head will reach to all corners of the build plate still. The only thing you will need to do is change the end stop bracket as this will clash with the new blocks. I've referenced a suitable one in the build instructions.
All required materials and hyperlinks to sources where applicable, are under the "Post Printing" instructions in the file.
Hope the info helps, feel free to drop me a line to let me know how you get on.