Registration form layout

Is there a way to change the spacing for registration forms? I have a form with custom fields. Each field has either two, three, or four radio buttons. When the form displays online there is almost an inch between each radio button and even more between each field. It spreads the form out too much and I would like to compress the form.

I would also like to keep all of the radio buttons in a single line. Would it be difficult to separate the field values with a pipe ( | ) instead of a new line?

Attached are two examples. The first is from the old booking system that I used and the second is from Events Booking. I would like my forms to be more compact.

Is there also a way to set the custom fields default to be assigned to selected events and allow selection of unpublished events to make design a little easier?