Great to see another Audiogoner going into DIY speakers! I'm working on a speaker with some similarities to yours and wanted to pick your brain: how do you find the balance of the dynamics from the G1 vs the 6.5" midwoofer?

My system is 4-way active xo, with a ribbon atop (Beyma TPL-150H) from 2kHz and up, midrange in the works but experimenting with Faital Pro 5" in a waveguide starting around 400/500Hz, dual 10" from 80Hz, subs below.

TPL-150 is very dynamic and I want a midrange to match it. I felt a single direct radiator had to be at least 8" to deliver enough dynamics but they beam before 2kHz and are scarce. MTM with two 5" would generate lobbying, so trying with a waveguide. 

Seeing your design makes me revisit my decisions, though.