Hopefully is an interesting way to put it icarus! ,
ive heard a common test with solid state rocket motors is to get a decent set of scales, first weigh your built rocket -include the presumed weight of the thrusters aswell, so presume we have 2kg shell and 2 500g rocket motors, (bigger the better haha), then total weight is only 3kg, make your self a test rocket, APCP if your going technical, or zinc/sulfur for a low tech- there is alot of diffrent compositions. (go for the solid state first befor venturing into nitros oxide as its a lot cheaper and less likley to go boom...), place your single motor on the scales upside down, light the bad boy up!! after securing it in place obviously, film the results of the scales, this will show you a good estimate of its actual lifting capability (3kg was an over-exageration) but on your video it shows 3.2kg of lift, this means you would only get 200g of lift, give a good error of margin and make sure your rockets will produce a excsess amount of lift, obviously if you had 2 stages your rocket would get faster expentionally as it gets lighter.
Hope my little paragraph made sense to anyone reading it haha...