[galaxy-user] galaxy cluster nodes from the cloudlaunch site

Dear Galaxy users, I created galaxy instance using galaxy ami the first time. When I re-launch via cloudlaunch site the 2nd time, I have question on adding cluster nodes. There are several pull-down options for the nodes type, no matter which type I choose, they always generate nodes with only 15gb. Is there other option I can have option to define the root space for the nodes? Thank you, Kathryn