Rocket Mass Heater Help

I have completed my RMH. It has a 5.5" fire box with a 6"round pipe casing riser with about 4" of vermiculite around it. The 55gallon barrel is little over 2" above it. I have 8" ducting that is about 20' long that exits the the house through the pre existing fire insert chimney. The 8" ducting traverses at a slight rise to the pre existing insert chimney. Currently the 8" ducting is not securely fitted but is pushed up to it because of the damper that was part of the insert.

After about 1-2 hour burn the top of the barrel is 350-500F. Is this a normal temps range compared to other RMH?
The 8" ducting does not get very hot and is leaking condensation at a couple of the joints.

The barrel is about 90% exposed. Do I need to put more cob on the barrel to get more heat through the ducting and prevent the condensation problem?

Is there potential of harmful gases not exiting the house because the ducting is not snugly fitted into insert chimney?

Thoughts and Comments surely appreciated.

Alan

the condensation problem is that your system is still wet and new. they all do the same thing for a few days till everything is dry. yes your heats are normal for a well insulated system. Kick back and run the stove till the moisture stops. Wont be long and you will be very toasty.