My opinion, stick with 15s. So many more sizes available in 15s than 14s. With all the new cars now with 16s thru 20s, they (the tire companies) will eventually forget all about us guys with 14s.
All things being equal the 14's will give you a 1/2 " front rake and will hardly be noticeable . I run used tires on my hotrods = cheap and I never put enough miles on to justify the price of new ones .
I think a 205 or 215/15 up front and a 235 or 255/15 out back would give you what you're looking for and keep the wheels all 15s. That's what I'd do anyways...........