I'm looking forward to extra MCCs in the new model. I've hit the limit on my T3: it has 120+ of the most common 2, 3 and 4 character combinations programmed, plus the same combinations again with an initial capital letter if I combine them with shift.
I'm thinking of using Ctrl + existing MCC to output whole words with a space at the end to layer on extra functionality. For example my 'h' and 'e' and 'a' produce 'hea', a common trigram, and I'd like 'h' + 'e' + 'a' + 'Ctrl' to output 'have '.
I'll use Alt and Num for alternates.
With the ability to switch layouts on the fly I think I'll move function keys and mouse buttons (very, very rarely used) to a different layout.
Interested to hear when we can start designing layouts! Especially if it'll be before the new hardware is available.