Help with wheel offset's

So what is the offset exactly? Is the standard 63 measuring from the hub to the arch? So running a 20mm spacer reduces the distance to 43? Or am I wrong?
 
Standard is 68, the ones i had in the above link are 45 so it would be like having 23mm spacers on. Offset is the the measurement between the inside hub face of the wheel to the centre line of the width of the wheel, so different width wheels can make a difference on how far the wheel sits in/out even thou they have the same offset.
 
After a few days searching and speaking to several people I'm going for the pro race 1.2, but I can only get them in either

Et45 but would be 7j
Or
Et50 and would be 7.5j

what should I be going for? I know I can get the right size from other places, but these are under £400 for a set!!
 
Quick bump to this thread. Would 7.5j wheels in offset ET40 work on the Clio or look ridiculous?


Sent from my iPhone using Tapatalk
 
Quick bump to this thread. Would 7.5j wheels in offset ET40 work on the Clio or look ridiculous?


Sent from my iPhone using Tapatalk

40 would stick out a little too much I think, it's the equivalent of using 28mm spacers on standard wheels.