Disability Benefits: Significant Gainful Activity vs. Trial Work Period

In returning to work, as a self employed person I have some questions. It is to my understanding, that a title ii recipient ssdi can start a business and then go through the 9 month rolling 60 month test on work(80 hrs) and net income( $780/mn appx) and then an EPE(36mos) - that criteria sounds Good, but if they are a Solo member, then they are deemed invaluable to the business -even if it makes no money. The single member in this example would be classified as performing SGa immediately would he still get a trial work period, or not ? I know that a 2 member company can have a disabled employee and not subject to the SGA if they somehow limit their activity to 45 hrs. Or less than half - how can a single person ever get back into working if they can't Try more than 45 hrs w/o triggering a SGA ? How are SGA and TWP related for single member companies ?

Disability Benefits: Significant Gainful Activity vs. Trial Work Period