Missouri and Arkansas seem pretty consistent in their signs. If I have familiar clear road and good sight lines I can take a 25 MPH corner at 60 to 65 indicated, and have good reserve, as indicated by chicken strips on the tires. That said, "pretty consistent signs" does NOT mean 100 % consistent. So I always size up a corner visually, and compare to the sign. If I think a corner is a 40 MPH corner, and the sign says 30 MPH I go with it. If I think a corner is a 50 MPH corner and the sign says 25 MPH, I will slow down to around 35 to 40 all indicated again, my mental corner computer is not 100%. There is no crime in that either, as long as you remember that! There is no crime in taking a corner too slow, there will be another day. As opposed to too fast, it is the best option.
There is one nice wide open 15 MPH marked corner in Kansas that I play on, so far I have it at 60 indicated, but I think due to wrecks the county put an over conservative speed on it. It is WIDE open, 1/4 mile visibility minimum, so I can use all the road, which does make a big difference. I think 70 would be about the limit, 60 is a big thrill though. I always pre-ride it to check for dirt, sand etc. Then I go back a few times.
Much of the time, I do not get the delicious horizontal acceleration pushing you into the seat on a corner, there are very few roads with good enough sight lines for that around here. But when it happens,