I'm quite familiar with MSVC's command line and I'm quite confused on what you mean "the above commands are specific to 32-bit Python"

"/LD" is available for both 32-bit and 64-bit compilations, it implies "/MT" to the compiler and "/DLL" to the linker.

"/I" is available for both 32-bit and 64-bit compilations.

Python's lib files are named exactly the same between 32-bit and 64-bit versions.

The only thing platform specific in MSVC is the compiler. Visual Studio's C/C++ build tools ships with 4 variants of MSVC:

2 32-bit versions, 1 for targeting 32-bit and the other for targeting 64-bit (32-bit native, 32-bit cross compile to 64-bit)

The same is true for the 64-bit versions (64-bit native and 64-bit cross compile to 32-bit)

Internally, these are known as: x86, x86_x64, x64, x64_x86