You cannot make it bigger...and as for other dragons: 157 is wyvern, 122 dragon skeleton, 158 wurm, 184 velious dragons, 192 clockwork dragon, 195 black and white dragons, 196 ghost dragon, and 198 prismatic dragon. Thats all i know, and as for what zone they work in...no idea, sorry. Also...if you go look at readme, you can get a list of race numbers...print it out and you have an easy reference
. Hope this helps.