80 seems to be the sweet spot. Here are some more numbers.
Average combine numbers for WR's and OL (
https://www.mockdraftable.com/positions):
Here are the same numbers in Madden with with average WR (90 SPD, 91 ACC) and average OL (65 SPD, 79 ACC):
Here are the actual differences when compared to combine times (the closer to zero = the closer to actual times or position differences).