I always end up keeping a few plates spinning in the air at once, when one gets me beat-down, I focus on the others. Pick the low hanging fruit when you need to see some instant progress, and take one step at a time and you will not seem so overwhelmed.
With regards ti self-confidence on design - that's a hard one. Nobody seems to have time to comprehend concepts (run it by someone) at the level of detail that is needed to make a decision as well as the originator. So you have to trust your math and gut. Demand evaluation is the most fundamental risk in a project viability and often is the gamble that either pays off or collapses a business project, more so than technical feasibility assessments. This is because costs can be recouped if demand is sufficient.
years to make & patent. May have been a good idea in the 1950's - I plan to be in the hole for a while on that one, however hoping 3dskydome will be more in line with today's consumers.