Ironically I had the same problem and this small piece of css saved me when I was dealing with a free format table (class nice) with alot of radio buttons. Seems its browser dependant what the result will look like. Chrome and Firefox expand the activation area for a radio button, whereas (old) versions of IE could scale the radio button itself to given dimension:
.nice input {width:30px;height:30px}
Suppose you can also check object's css with javascript, so there is no mandatory need for a free format question here
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CSI