Trying at home is a good taste test, but you need to cook it on your backpack stove and pot - try to simulate what you will have when backpacking.
As for volumes of food needed while backpacking- that is something you have to do backpacking, trial and error. Some people eat a lot less while backpacking, others more. Pay attention to what food ends up back home- you are taking too much or stuff you really do not like if you do not eat it while out!
Honestly, some stuff I like when I backpack, is really a bit disgusting when I eat it at home. My backpacking hunger and taste is really not the same as at home. The "try at home" simply eliminates the really bad stuff.
The big difference when backpacking is your gut. Lack of fresh vegetables (fiber) needs to be supplemented with other types of fiber. Also, some food seems fine at home but may make you gassy if eaten while backpacking. The reason I do not eat commercial FD meals, is that my gut cannot tolerate it.