Checked and adjusted my TPS and STPS yesterday, all readings at the sensor connectors. TPS at 1100 Ohm closed and 4217Ohm at wot. As per spec.
STPS set to 799 Ohm closed. Went through the Airbox to hold the secondaries closed after removing the air filter. Found that if you actuate the secondaries via their common rod underneath the sensor, I.e. outside the airbox, you get the same result, so there is actually no need to remove the air filter. Pushing up on the rod from underneath closes the Secondaries, pulling down opens them.
All adjusted, restarted and found that the fast idle was also much better. Went for a 30minute ride and much improved low speed throttle response. When hot, I adjusted the manual idle speed to sit just above 1000rpm (indicated). Happy so far. Thanks for the valuable input here, much appreciated.