Your rafters are probably 2 x 6's, you need a minimum of 8" so you have air flow above your 6" insulation. Rip a 2 x 4 in half and nail it to the underside of the 2 x 6's. Make sure to nail the factory sides, (the 1.5" side) not the saw cut side, so your Firring strips are all the same thickness.
Ceiling insulation can be installed yourself. Purchase the insulation at a big box home improvement store. It comes in rolls and just lay them on the ceiling.
The difference in the insulation, provided by wet and dry animal fur is that, the wet insulation fur gives low and weak insulation, while dry insulation fur gives a maximum insulation.
In the ceiling and the walls
Venting to eliminate moisture and insulation in the ceiling.
Insulation.
For insulation purposes to the ceiling
The fur of a coyote provides warmth, insulation, protection, and camouflage.
for insulation
fat and fur
Insulation
What is your question here? If you want to keep the insulation from sweating get thicker insulation. You probably have 3/8 thick insulation; increase to 1/2 or 5/8. It is possible that your suction line is freezing up and when it thaws it soaks the insulation causing it to drip. If you can't prevent the leak, use a vinyl ceiling tile, like Ceilume, in that area. It won't absorb moisture and is easily cleaned.
See Discussion page.