First suggestion will look worse, as wheels will sit further in the your old wheels, and from the rear itll look silly going skinnier wheels. you most likely wont notice, but the handling may become slightly worse due to be the wheel track being smaller.

Your second suggestion on the other hand sounds better. It may come out to far though due to the offset vs width as the 245 will have a bit of fat
what size tyres do you currently have? and is the car lowered/planned to be lowered?
something like what team_v suggested would be best...

Try these. in your case id be watching the over all tyre diameter and how much the wheel in and out away from the strut and arch.
Custom rims, wheel tire packages for your ride - RIMSnTIRES.com
Wheel Offset Calculator