One suggestion, with respect to the use of the brass washers - you might want to consider using brass faucet seats ( seen on the left side of the picture), instead.
True, they are more expensive than washers... a little more expensive, given the skyrocketing price of brass at the hardware stores... but they are more visually appealing, and seem to fit perfectly with the function of implementing a pushbutton or framing a large LED ( such as Adafruit's new 8 mm neopixel devices, or other 10mm ultrabrights ).
Last I checked, you can buy packs of 25 at Lowes or Orchard for about $25, or a buck apiece.
@Max I was going to suggest you used one of the usual TV ratios of 4:3 or 16:9 but I think @perl_geek's comment
You might want to consder employing the Golden Ratio (1.618 : 1, close enough for government work) in your rectangular layout.
is spot on - old TVs were't wide enough and new ones (16:9) always look too wide to me. I did come across the Golden ratio, as the Golden rectangle, years ago and the Wikipedia artilde on it is good (if a little over my head maths-wise :-) :
What are the engineering and design challenges in creating successful IoT devices? These devices are usually small, resource-constrained electronics designed to sense, collect, send, and/or interpret data. Some of the devices need to be smart enough to act upon data in real time, 24/7. Are the design challenges the same as with embedded systems, but with a little developer- and IT-skills added in? What do engineers need to know? Rick Merritt talks with two experts about the tools and best options for designing IoT devices in 2016. Specifically the guests will discuss sensors, security, and lessons from IoT deployments.