You can actually try it on your Windows computer. May be that's all you need, and that's ok.       My layout is based on two things:   - tri-state layers used in Planck/OLKB boards,   - and SpaceFN layout.       The former allows to have four layers controlled by two keys. It works only if you have a programmable keyboard.       The SpaceFN layout can be used on its own, on any regular computer, provided you can install a program to it.       The idea is to turn space bar into a modifier key. That is when you hit it once it works as a space bar. But when you press and hold it - it activates another layer, like Shift or Control. This post on Geekhack.org  describes this idea in more details.       For SpaceFN (when I don't have my ThumbsUp! keyboard) I use TouchCursor  utility.   You can download and use it for free.       To use my layout - launch TouchCursor double click on its icon in the clock area to open the configuration window. Change any of t...
User manuals and related materials for ThumbsUp! keyboards I sell on Etsy and eBay.