Help with my Keyline! Trying to determine my keypoints and keylines on my farmland (goat farm)

Hello! I am looking at implementing keyline design on my fields. I will upload a map of the contour lines and water flow on the land. It's a goat farm with permanent pasture on field 16 and rotating temporary grassland and cereal crops on fields 27 and 28. These fields have the main problems areas and have been experiencing issues with waterlogging in the South East corners on fields 16 and 27, 28 and also the South West corner on field 28.  
Id like to change my tilling in line with keyline design to help distribute water flow and prevent erosion... currently i till up and downslope. There are ditches along the border between field 16 and 27 and 27 and 28. My idea is to do keyline tillage and perhaps keyline subsoiling to help more even distribution of water. With climate change the precipitation is becoming much more erratic....

I'm struggling a fair bit to determine the best keylines for tillage and subsoiling and cropping.

Thanks so much in advance!

Heres another useful image of water flow

Welcome to permies!

Heres another useful image of water flow

That's an interesting image - where do you get that from?

I'm not experienced in keylines, and suspect if you just started ploughing across the slope rather than up/down you will see some benefit. As I understand it the keyline ploughing is to plough slightly down hill, but towards the high spots so the water stays in the soil longer and spreads rather than going straight to the lowest spots.
I have had a go at annotating your simple contour plan - red dotted is the high spots, blue/green is the natural valleys/low spots and orange is my suggested ploughing directions. Hopefully someone who has studies this more will confirm whether that makes sense!

Plowing on contour would help a lot even without paying attention to the keyline.