Fanning is the toughest part even with a single blade. I imagine the thinness becomes even more of a problem with two. Just keep splitting it up and building from the bottom is the best idea I can think of.
Also, some colors help in reducing how thin the fan is. Letters especially. When I put mohawks rock in my hair, it draws the reader to read the whole word and not see the gaps as much.
i am just holding it up and then hairspraying it, i dont use gel anymore because its too heavy, but when i use spray i usally just comb it up, spary it , and blow dry it utill stiff
when my mohawk gaps up like that I apply some hair gel or hair spray and try to break up the hair that would fill the gap, and comb it out just a little so the hair around the gaps just come togeather to fill it in.
After you have it up and completely dry and stiff you can comb it out again and then re-spray
i noticed that certain things may aid clumping and gaps. i was doing my hair with soap and glue and I would have a few areas that would almost always gap and I have now started using knox due to the length of my hair and though I am still playing with the method I have found I have gotten a MUCH better fan for the most part. Sadly, the top of my head has a lot finer/thinner hair than the back but I still think it is fanning much more evenly and better.
A hair straightener could probably not hurt either but I can't write a testimonial on that because I don't have one yet =p