I am building a p51 and am getting close to the covering stage. I bought a vid on how to go about it. It says that any imperfection will be seen through. Well i have sanded and sanded and puttied and sandedand puttied and sanded trying my best but will every little crack between twoo peices of wood be shown? How do i know when it is good enough? Or is pretty good good enough. I realize it is a tough Q buti know nothing about covering a plane(or typing). and just want to know there may be an end to my struggles.

Any help or comments will be very helpfull.