I have recently published a short article about a pattern I have added to my layout (argenkiwi/kenkyo on GitHub): thumb-chord one-shot modifiers. In short, it consists of defining a chord composed of a home row key and the space-bar (or a thumb key) and bind it to a one-shot modifier. For example: d+space=oneshot(shift).
I was a bit skeptical about the idea before I tried it, but it turned out to work pretty well for activating shift, altgr and my custom symbol layer while typing. Has anyone tried something similar?