Wow. A 19-letter ambigram is a tough piece of work, and I think you did a pretty good job already. I would love to offer some help but I feel like I'd need a lot of time to find ways to improve it, and I really have to go to bed early tonight :-)
One question though: Have you considered using a vector drawing tool to do this? If not, I'd suggest you do. Inkscape, for example, is free and awesome. It may take an hour to get used to, but it'll be worth the time, particularly for your project where you have to duplicate the halves all the time.
Hey, thanks Sebastian.
I appreciate the Inkscape suggestion and have already downloaded it - still figuring out the basics. I've found a couple online tutorials for vector font creation, but if anyone has any favorites, feel free to pass 'em allong. Also, for all the font masters out there - anyone know a font that is similar to what I have here (I realize that my style is inconsistent)? Im looking for just some inspiration on how to standardize my font across the various letters. I like the "Haile Rober" section of text best if that helps.
Well, as for font suggestions, google "Celtic Fonts" or similar terms. You could also use the category/tag systems on sites like myfonts.
I'm not sure whether "vector font creation" is the correct thing to look for. You will probably find tutorials for FontLab and FontForge, both of which allow you to design the single letters instead of whole pieces of artwork. Instead, get Inkscape and look through the online documentation (or just play around for a bit, that works too). There are also some great screencasts on Youtube that explain vector programs quite well.
If you want typographic advice on how to draw good letters, I'd say look around in this forum. There are many threads like this one with plenty of links to type design tutorials.