I'm not sure where that fits in. Are they wanting to use a 64-bit cl.exe and a 64-bit linker to make 32-bit output? Does mixing and matching the cl.exe and the linker change how much memory the linker can use?
I am baaarely familiar with Microsoft-world development.
You can't use a 32-bit cl.exe and a 64-bit linker to produce 32-bit binaries if you're doing PGO (which is the whole point of this "using lots of memory" issue). In particular, the 64-bit linker can't produce 32-bit binaries when you're using link-time code generation, which PGO does.
I am baaarely familiar with Microsoft-world development.