a decent turbo specialist should supply the turbo with the correct actuator for the desired performance (min 10psi spring), personally i would fit the uprated Forge Actuator with a 10 psi spring.
You need to drive the car in stock software mode with the n75 valve disconnected so that the max psi you'll hit will be actuator spring pressure (10psi). Drive the car smoothly and gently (keep the revs below 4K). I run my set up on a stage 2 APR remap adjusted with lemmiwinks for fueling etc.
Best advice is to take it to a tuner who will fit and remap it at the same time. This will save you loads of time stress and ultimately money in the long term. Most tuners will charge less than £250 for fittting and since they have the tools, ramps, experience and offer a warranty its a no brainer.......speaking from experience here.