I have gone back and done a little research on the Yoshida family, Shidare Yanagi Ryu, Angier Sensai, etc. I really haven't found anything within this system applicable to customizing a katana, save only, say, using the Yoshida mons for the fuchi, menuki, etc. As such I am going to use personal preferece for customizing the swords.
I intend to use dragons on the Kiyomaro katana, partly because of the imposing size of the weapon, but mostly because dragons in eastern cultures are powerful guardian spirits who protect and watch over the people and I, as a (at least an armchair) warrior want to embody that spirit in my soul and in my weapon. That, as warriors, we preserve and protect everything we love and hold sacred, right and just. Consequently, the sword will embody both the spirit that I seek and strive to attain in my training as well as being a tribute and honor to the warriors, past and present, who have fought, spilled blood, and even gave their own lives for us and our causes. We owe them all that we have and ever will have.
The Medium katana will be done in the theme of Cherry Blossoms. I chose this for my interest in Japanese martial arts (Sakura are the offical flower of Japan) as well as represent the delicate beauty and fleeting nature of life. It reminds me always to keep my mind open and be observant and more alert of myself and my surroundings and to enjoy the life I live.
Thanks for the input, Brian.