hi, first post here so please be gentle .. i was at carlisle over the weekend and came across a set of 4 wheels and just as i started to try to measure the backspacing, i was practically drowned standing up .. so ... i did a very cursory measure at 4 to 4 1/4 bs .. i know that 4 1/2 is the desired number, but just how critical is that other 1/4 to 1/2 inch? .. the guy doesnt live far from me so i'm thinking of taking a second look later this week .. any help is appreciated ..(66 fastback, suspension is stock for now) thanks