Wheel Offset????????????

Hey everyone. So with our 66 mustang coupe, we are shopping for a new set of wheels. Found the ones we like. American racing torque thrust II. 15x7 in the front 15x8 in the rear. It's a five lug all around. What I'm wondering is choosing the offset? No freakin idea. Sure I could Google it but quite honestly I am enjoying all the help and feedback from y'all. Richard and Rusty have been exceptionally helpfull. Any advice? Thanks guys. Happy wrenching everyone

Ok thanks guys. Good place to start. The ultimate goal would be an inch wider and a inch taller in the rear. The front we want an inch lower and fairly skinny 2 inches narrower . Want a nice rake look to it. Also skinnier in the front will hopefully help the wife to turn as its manual steering as well. I should have posted these sizes earlier

Rear is currently 205 70 r 14
Front is currently 215 60 r 14
Pretty sure they are 7 inches wide. So if we are putting 15s on technically I would have the extra inch in height on the rear right? If so what size tire would make it s inch wider? As for the front I would need to go 2 inches lower and 2 inches narrower correct? What tire size would that be? And lastly. Would the 7 inch rim work for width on front and rear or would I have to go with a 6 inch rim in front and a 8 inch rim in the rear?. Aye carumba. So confusing. Any thoughts guys? Thanks again. Happy wrenching everyone