RE: Weird(?) gyro issue
The 6965 is rated at 6V and should yeild a speed of .10 and at 4.8 is will give you a speed of .13. This is rather slow by todays standards. It is workable as long as you use 6V. The problem I suspect is your servo arm is too long. For a 500 size heli I would use about 10-11mm at the most. Now if you are using a DX8 your rate would be about 27% and not above 50% for HH. Your clue was that it wags in rate mod. Also make sure your gyro know you have a digital servo.
As far as set up, you should have made sure your servo arm is 90% to the tail boom and the slider centered. The difference in the two gyros id due to the fact that not all makes give you the same throws and servo control and response. Read up on the T7000 to see if you have it programed for your equipment.
Jim