A37 - it was, under the CAA IR, a requirement that full N1 be used for a non A/T g/a - I don't know where EUOPS sits on this. That is why it has 'traditionally' been so, since the factors the A/T uses to calculate 'sufficient' g/a thrust are not available to a pilot.
Most Ops Manuals have (should have) a para which says "when a safe rate of climb has been established the N1's may be reduced to avoid excessive climb rates etc etc" or words to that effect. In other words, g/a N1, flap, gear up, throttle back.