Increase option set drop down height

Hi,

I have a couple option set fields with 10-15 options. Clicking on the drop down only displays 3 options before you have to scroll down. This is a bit cumbersome from a users perspective.

I added some spacers on the form below the option set field, but the max it will display is 6 options. before having to scroll down.

Is there a way to increase the drop down size to display 10 or all of the options? Or is there a way to get them to list as a radio button so all the options are visible to users?

Thanks