As someone who used to cycle Dartmoor a lot, I have a technique for normal cattle grids.
Speed up at much as possible, grip the top tube with your knees, cling onto your hoods with white knuckles, close your eyes and pray to any gods you can think of. It's always worked so far.
In all honesty though, stop pedalling, hit them at 90⁰ and do not turn the handlebars and you're fine.