MkII H frame quad now flying.
Frame weighs about 60g less than Mk1 with much more room and accessibility to the nose sections. The arm O rings mounts are more firm than the Mk1 but vibration levels about the same. All RAW x,y,z accel vib about +- 1.5. Its possible to fly without reversed motors but the YAW rate is still much better with them reversed. As the arms are enclosed there is no problem if an O ring brakes and it has been flown with two missing on the same side.
I am now working on an internal nose gopro gimbal.