Yup, mee too I went to dual motors after a stock motor went south. Looked at HH's nice photos of his beautiful mount and made one up to identical dimensions--took me about 2 hours in the machine shop, so I figure it's a hundred dollar part . Worked much better with my g90 but the system was noisy and heavy and still left something to be desired performance-wise (2 or 3 ratchets back and forth before the tail would settle down after hard rudder inputs) and you still always strike the darn rotor on the floor.
So I decided to try the direct drive system. It definitely flies much better and the prop is shorter so you don't strike the floor all the time. I can even operate off my short-pile carpet now. Also much quieter. Sounds like an angry mosquito is chasing your heli.
And I found the parts hanging on the rack at the LHS.
There is a downside though.
I tested all three systems for weight, and current draw at the same thrust (as close as I could hold it to about 50 grams--way more than you'll ever need in flight) in the lab today. They say a picture is worth a thousand words, so here's seven thousand words: