I appreciate all of the interest in the Si5351A Breakout Board that I have available on OSHPark. I apologize for not having this available sooner, but here is a GitHub repository which hosts the KiCad design files and a PDF of the Breakout Board schematic, which lists the part numbers for the reference oscillator and the output transformers so that you can order your own. Also the few passives on the board are size 0805.
This, along with either the avr-gcc library or the Arduino library, should get you going in generating all kinds of clocks and local oscillators. While this board seems to work fine in interfacing with the 5V Arduinos that I have, I worry that comms might be iffy, so I’m going to add simple MOSFET-based level conversion to the next iteration of this board. Keep an eye on the blog for further developments in this area.