STEERING TOO SENSITIVE

The trouble with fitting PS to a manual steer system is the gearing, the ideal ratio is 15-1 or less. You have 18-1.

I think unless you can make some major pressure reduction adjustments, steering will always become uncomfortably lighter the faster you go.

The info on pump adjustment is excellent & very interesting, I hope it works out! If not, try disconnecting it & put some decent pressure in your tyres.