Brand New Multi-boot Boutique Computer

Hello. I am setting up a very particular computer with some interesting requirements. I have already put it together, and installed the OSs. However, a few anomalies came up and I would like to ask the community on how to address them.

I am running a Gigabyte GA-EP45C-UD3R with the ICH10R + P45 chipset.

Want to multiboot:
Windows XP Professional SP3 OEM x32
Windows 7 Professional x32 Retail Upgrade
Windows 7 Professional x64 Retail Upgrade

I am running 2 WD Caviar Black 1TB hard drives in RAID-1.

XP is going to be the main system, with the 2 W7's as prototypes for work.

I used the RAID BIOS to create a single 1 TB Mirrored drive.

I installed the 3 OSs in the above order. I partitioned 100 GB for XP, 150 for W732 and 150 for W764, and am leaving some unused space for possible future OS installations.

All was well, and I was able to get all three OSs on, but 2 things had me worried.

While XP and the 1st installation of W7 seemed to 'play nice' by having identical drive letters, the 2nd installation of W7 used its partition as a C drive, instead of the G drive the other 2 OSs read it as... I could not change this in Administrative tools.

The other anomaly is that XP is referred to as "Earlier Windows" which is fine, but both W7's are listed identically as "Windows 7". Being that this build is for a non-technical client, this will prove to be a dissasterously confusing situation.

I have time, and I would like to know, what is the ideal way to install these 3 OSs (what order) to allow all 3 OSs to have uniform drive lettering and how can I change the boot menu titles? What is the best way to pre-partition the drive? Should I just use XP to make 3 partitions?

Also, am I to assume that the OS controlling the boot up will be the last OS installed?

Thanks!