Bigger wheels & tyres

Just been looking over the rules governing the fitting of bigger
wheel/tyre combos in various states & it seems the rules are all
pretty mach the same.Max increase in wheel width is 25mm and max
increase in overall diameter of tyres is only 15mm!.My question to
anyone who might know, is -can we use the wheel sizes from the syncro
16" as as a standard wheel size & then add 25mm width & 15mm height to
achieve a legal big tyre size. Thanks to any one who has an answer to
this. Eddie Bergodaz.