You're welcome. It's surprising how easy chainloading really is.
And another good thing about chainloading is when you do install grub to root while installing on whatever partition, is that you can install a different linux over top of the linux that was there, install grub to root again, and never have to re-edit your main grub again.
I found this out a while back when sidux come out. I had SimplyMEPIS 3.3.1-1 on hda7 and when I installed sidux there it just booted. My grub screen said that it was still 3.3.1-1 but sidux booted seeing how sidux was installed with grub to root. Then the next day I put SimplyMEPIS 3.4.3 on the partition that sidux was on and I still have not bothered to change my main grub.
When I refer to my main grub I mean the grub that is installed to the Mbr of hda. That is the only grub that you want to edit. Leave the other grubs, on other partitions, that are installed to root alone. This makes testing a new version of MEPIS, or any linux that can install grub to root, simple.