[Jim Doodle]

Nice wheels!, the tyres will probably be underrated at that size. A new set of tyres might set you back 200-300.

It doesn't mention the width of the wheel just the tyre. I think most are about 8 inch wide. The offset is about right as long as they are 8 inch wide

 

[Jim Doodle]

nothing on there site

http://www.inovit.com/products/tarmac.asp

With the tyre load rating you want to around 100, which can be hard/expensive on lower profile tyres.

 

[Jim Doodle]

It's not much to do with the letters more with the numbers,

http://www.blackcircles.com/general/sidewall

 

[Jim Doodle]

Offset is the measurement in millimeters from the wheel centre line to the wheel mounting face.

The offset is described by the term ET, which is from the German word 'Einpresstiefe' translated as 'insertion depth'.