IMHO this is popular mistake that additional volume gained by making airbox smaller - it is not true, at least not for european bikes. My airbox completely same
Tank just fits right in place, nothing to change at all. Looks like additional volume gained by making rear of tank a bit steeper, top a bit higher, a bit more there and there - and here you have 3 morel liters. Also some addtional volume comes by making rear of tank a bit deeper (hence different fuel tap).
All you need is post 2001 tank and post-2001 fuel tap and filter. And this is what burned my pocket

because new fuel and tap from Honda cost about 150 Euros.
I took cap and sensor from my old tank and it fits new tank perfectly.