How Do I Enlarge my (C:) partition with Disc Director 11 Home in Windows 7 Home Premium (64-bit)

I'm trying to Split my Data (D:) volume (Primary, NTFS, healthy, already contains some saved data) and Merge the new, empty, volume with my WIN7 (C:) volume (Primary, NTFS, healthy, Active, System, Boot) and I'm having no luck.

When I Split Data (D:), I get a new volume, which is Data (G:) (Logical, NTFS, healthy). So far, so good, and I Commit.

I don't know the difference between logical and primary, but I assume that in order for me to Merge volumes, they must match, so I right-click Data (G:) and select "Convert to primary". Then I commit.

So, I now have 4 partitions in my Disc 1 bar. These are, in order from left to right:
-RECOVERY
-WIN7 (C:)
-Data (D:)
-Data (G:)

What I would like to do now is Merge Data (G:) into WIN7 (C:) so that I effectively enlarge WIN7 (C:) while allowing Data (D:) to retain all its characteristics - I don't want any applications that save/retrieve data to/from (D:) to get confused. The problem is that, when I right-click on WIN7 (C:) and select "Merge volume" (WIN7 C: selected as "Main" in step 2), it appears I can only Merge a volume with other volumes that are adjacent on the Disc 1 bar (apparently, location on the bar helpfully represents actual location on the physical disc).

Is there a way I can swap the locations of Data (D:) and Data (G:), putting (G:) adjacent to (C:) so that (G:) may be merged into (C:)?

...

I suspect I may have found the answer myself, just now, but it seems like a bit of a kludgey workaround. I'll describe what I have in mind here and hopefully someone will let me know if there's a more elegant, straightforward way to do this, or if what I've come up with is the "real" way to do this, or if what I've come up with will even work at all. So, here goes - is it a good idea for me to work as follows:

-When I initially Split Data (D:) (into D: and G: volumes) check the box next to "Move selected files to created volume" and select all files, then Commit

-Convert Data (G:) - the new volume containing all the data which used to be in D: - to primary if necessary, then Commit

-Merge Data (D:) (now empty) into WIN7 (C:) (WIN7 C: selected as "Main", of course), then Commit, leaving me with 3 volumes, from right-to-left on the Disk 1 bar:
RECOVERY ; WIN7 (C:) ; DATA (G:)

-Right-click volume DATA (G:) and select Change letter, changing the volume's letter from G: to D:, and Commit

...?

Am I nuts or is this the way to (boiling it down here) take a chunk of space from D, give it to C and avoid my apps and OS having any confusion or interruption accessing D like they always have?