Cindy I agree with you about how the male plays the net.
A lot does ride on how well the male can cover and poach when at the net.
But I still believe that any pair of 4.0's that are average or above average would return the 3.5 females serve well enough to mitigate the opposing teams male trying to poach the net.
A 3.5 serve is usually slow enough and lacks enough spin that its fairly easy to A. Lob a crosscourt shot deep pinning the 3.5 server in the back court or B. if the male is poaching too much hit one down the line to keep him honest. Then once you keep the male honest and he cant poach 1/2 to 3/4 across the net then its easy to blast returns at the 3.5 female who usually has zero chance of getting solid contact on it.
Racquet: Wilson 6.1 95s String: ISOSPEED Baseline Control 16 @50lbs in mains, Random multi/syn gut @55lbs in crosses