campaign configuration

[vjonvicidial]

I am setting up a campaign with 8 agents.
the campaign requires to dial out calls with at least 4 agents available to take inbound calls.
if 8 agents are logged in it should dial 4 calls if 7 are logged in 3 calls and so on.
it has 3 list based on priority the the first list should be called in order UP (last added number first) and then second list and then Third.

What i am trying -

Campaign - configured with 8 agents and 3 lists
- List order UP (to dial last added entry first)
- Dial Method - Ration
- Auto Dial level - 1.2
- Available only tally - Yes
- Dial Level Difference Target - -4
- List mix with 60% as first list, 25 % as second and 15% as third.

does this sounds correct or there is better way to achieve it.