Since your method does not allow for setting partition size via Diskpart, I might do that manually with a Linux LiveCD (PartEdMagic on USB flash drive) and then start the Windows install. I'm sure it can be done with diskpart but I'm not familiar with the commands.
The Linux method will allow me (via a GUI) to set partion size, format to NTFS with designated cluster size and set flags such as boot, active, primary, system, etc. My concern is the 100MB "Sytem Reserved" partition that Windows 7 creates. I have seen Win7 installs where this partition does not exist... so I'm assuming it is not actually required but is just the "Windows way" of doing things.
I have, on past systems, installed Windows 7 to a single, pre-created partition and it did not create that smaller 100MB partition. This whole post is about making sure that a certain percentage of the drive is NOT partitioned but left free for the SSD's "scratchpad" for "read-move-erase-write" operations to extend longevity of the drive. The bigger the unallocated area, the longer the drive will last. This issue is, I believe, unique to Intel SSDs, but I could be wrong about that.