So about 100g (4oz) lighter. As for other lenses, the 180mm Super is good, the 135mm can be useful. At the wider end the 65mm maybe too close to the 80mm. The 55mm can be variable, but that is pretty wide for 6x6. The 105mm is a nice long standard, but close to the 80mm. The 250mm is probably equaled by enlarging the 180mm Super, and that lens is a stop faster.

it sounds like the C220 with the 80mm f3.7 is a nice light unit - don't be in too much rush to add extra weight and choice 8-)