There aren't many rules that you need to worry about here on the Ranch, but one that we take very seriously regards the use of proper names. Please take a look at the JavaRanch Naming Policy and adjust your display name to match it.
In particular, your display name must be a first and a last name separated by a space character, and must not be obviously fictitious.
For the browser question. GWT does a great job at handling browsers differences. I write and test on a Mac in the safari enbedded browser and the application always works in Firefox, IE, and Opera.