16 inch beam alloys or 17 inch savio alloy wheels

Hi. Collect fabia 1.2 tsi se mkiii cagey white with sunset glass and fogs on Monday. Originally ordered the 16 as above but since paid for the 17 as an accessory. The dealer thinks he has a buyer for my 16 inch. Reading the thread re upsizing in the octavia forum not sure I've made the correct choice... definitely gins look great but cost if tyres/comfort now concerning me... dealer knew nothing about the 17 as no one has ever ordered then there before! Also asked me if I wanted matt or metallic but couldn't show or tell me the difference... advice please??