Use Iris ThumbUp module to emulate space key on keyboard. You can rotate it and adjust to the most comfortable angle for your thumb. Using cherry MX silver complete with stabilizers just like actual space bar key.
To attach TU module you need:
For VS1R/VM6 use "+TU" variation of layout cover
For VB1 use "Thumb Cover TU"
Connect the cable into PCB Ground and any input signal you want (usually for Up direction).