Co-GP structure!

Any one have any insight on co-GP structures? For example, $100M deal with 60% LTV. You go to a PE firm to raise $35M of JV equity and co-GP puts in $5M. How do you structure this amongst the co-GPs? how are fees split? Do you create a hold-co for the co-GPs? how do you structure a win win situation in case one of the co-GPs doesn't execute their responsibility in the business plan? What would the water split look like? thanks in advance!