How do you pre-plan a multilevel dive or do you? Do you plan the dive using a manual approach (table or other method) or do you use a paid subscription software application?.
As an newbe OW I have not gotten to a point where NDL is a realistic consideration as I'm diving shallow at 75ft or less. Especially when I'm using NITROX below 50ft, but this is a great thread.
I do look at tables to get ideas and use the dive planner on my computers, but I don't believe they do multiple dive planning. They do not do multiple level dives. Therefore, they are my worst case senario.
So far I've only done a few drift dives from boats, so my turn pressure is the only real factor. For 30ft-40ft I've turned at 1250psi. At 75ft I've used 1500psi. Using these reserves it should be possible to hit my safety stop or boat then return to the bottom and still safely ascend with 800psi or more air. It is something I may want to do instead of accidentally leaving several hundred dollars of drive equipment at the open reef dive shop because it got dropped at the surface.