Need 15 -16-17 or 18's

My Signet needs an updated look and for the likes of my I cannot figure out not which wheels and tires I want to use, but which wheels and tires will fit. For the past 25 or so years, it's used 14" 5 on 4.5 - 7" wide steel wheels and as you know, tires are hard to come by except for BFG T/A and I dislike T/A's.
Signet now uses 205/70's on front and 245/60's on rear and both are basically the same height

What numbers would it need in both wheels and tires if running either 15 -16 -17 or 18's both front and rear to fit the program so to speak. If any other information is needed I will gladly give you more.. Thanks in advance for your time and energy :-)

The car itself has 74 Duster front discs and an 8.75 rear with a 2" lowering block, both are BBP.