Check the sticky threads at the top of this aerodynamics forum and also in the Scratch Building and 3D CAD forum.  There's some useful links in them to basic planform sizing guides to design a more or less generic style of regular model.  Also download a lot of the free plans and study them for planform ratios and structural building ideas. 

Plagarism in model design is a time honored method of learning.  So you may as well follow in the footsteps of those of us that have also copied a lot from those that came before us, who copied a lot from those that came before them....

All of this is to say that if you see a planform that suits you but it just needs some shape changes that keep the same area and moment arms or that change the wing tips to something  you'd rather have and maybe a different airfoil... then these are all valid and the model will fly pretty much as well as the design that you were inspired by.