That is misunderstanding, I meant:
1) Add at least three user assignable keys/slots to five already existing, so that user may activate any of eight snapshots using keyboard. (That is simple, at least on UI side and should not be that difficult in TM FX internals. It will not be more than 100 lines of code per key added. And changes in storing and reading configuration file.)
2) Possibly add feature that user may choose the key (instead of current F4 to F8), that activates that feature. That is more complex on UI side, but would be cool.
If 2) is too much work, or there are obstacles. Say ten assignable keys/slots could be used with fixed keys F4 to F8 and Shift/Ctrl/Alt (one of them) and F4 to F8. On Win it would be easy, I do not know about Mac.