Personally, I wish my returns had at least a 3-way valve between the two separate lines. I only have 2 lines at the pad, but 3 returns. It would be very nice to be able to balance the flow or turn off one or the other during closing etc. I'd say at a minimum, I'd go for 2 common lines that each split to 2 returns at the pad with a 3-way valve between the common lines. To go further, you could have a 3-way valve linked to 2 downstream 3-way valves that feed the 4 return lines. You could also go with four 2-way valves, one for each line.