This one is a little tricky. Ideally, you would have a friend or colleague help you out where you set their security to one of the roles you're supposed to test. If it's just you, you'll need to change your role from "Full Access" to one of the roles. Just don't uncheck the workspace administrator! You can change your selective access control too. Because your a workspace administrator, you'll be able to change everything back to Full Access.
Sure, no problem. Go to "General Lists". Assuming you turned on selective access. You should see a column in the General lists that allows you to turn on selective access. Go ahead and turn it on for the G1 and the accounts list. Then under "Users" Change your role and select the level of G1 and Accounts you want to give yourself.