The design idea was to bring buttons surfaces as close to the handlebar as possible. In most of existing solutions buttons are quite more distant from the handlebars.
Second operation fixturing is quite sketchy. I should revisit it later. However, the shape of the housing does not make it easy to hold.
There is not a lot of space to work with, so the wires will go through the back of the housing and exit on the side.
I am using high quality APEM IP series latching and momentary switch buttons.