Sorry I wasnt around to get back to you on the bath issue. Glad to see you came right!
Remember iguanas are one step forward and two steps back. Please dont be upset or think you did something wrong if he is not easy on another day. They are like a roller coaster ride and you will never know what to expect next. They only settle down much later, say after 2 years of age. But it is a FUN ride!
Dont worry about the puffing up etc., it takes a long time and lots of handling before Diesel will start trusting you. If you are consistent with the handling and shower him with love and soft words, you will maybe end up with an ig like mine that choose to clime on you each night, stretch out, close eyes and sleep like a baby.