Most judges would knock off more points for chrome magnums than original finish road wheels with brushed trim rings. If you use 15 inch and use original style caps, most will not knock you for the size change.
I use a set of 14 original restored road wheels with brushed trim rings and red lines to show. Then I have another set of "fun" custom wheels and tires for driving.
Really depends on what show and what level of judging.
Most local shows, Carlisle, and AACA no one will notice or know the difference. The Nats...... they will know!