On a similar note, I wanted to share that I thought to bend the terminals on the button 90 degrees to help make clearance. In doing so, it allows the button terminals to completely clear the PSU connector on the SF600. Because I'm bending the terminals and not the wires I belive this to be a good solution. I also looked at other buttons that are shorter in depth but won't offer the LED. If I went that route it would be nearly $700 for me to buy and have shipped, of which I'd be eating the cost (and there is already no profit margin on the S401). Sufficed to say, I believe there to be three options available right now:
1. Bend the terminals - I think I'll do this before anything ships and I'll do this on all buttons.
2. Include the collar I'm making - adds clearance for more peace of mind.
3. Leave everything alone and let the wires come in contact with the C13 plug.
I am planning on performing #1 & 2, while #3 is not an option for me at the moment.
Below are pictures of the front panel button without the spacer/collar installed but with the terminals bent flush both inside and out of the case.
Even with the shadows, you can see the back of the case proving there is clearance. Also, the wires are loose in this picture (no tension).
Edit: I want to add that better pictures are coming but my main priority right now is getting imaging done for the installation manual.