Brilliant advice from the community as usual. If I understand the OP correctly, the issue is about how to transition hung off one side to the other quickly. I'll leave well alone the question of whether hanging off is necessary or desirable on the road; I do sometimes and on rough surfaces it often helps stabilise the chassis provided the legs are carrying the body weight.
For a quick transition, bring the hung off leg back to the tank, grip the tank with both legs and slide the butt to the other side while also repositioning the upper body keeping the arms relaxed, then drop the leg on the side you've transitioned too. Tank grips really help. Ditto all the other points about keeping the CofG low.
Track training really is to be recommended but for a good read try the Haynes book 'Performance Riding Techniques by Andy Ibbott ( Foreword by Keith Code). ISBN 978 1 84425 697 6. Hope that helps