LinuxCNC 2.5 on Lucid to 2.7 on Wheezy, save G540 configs or redo?

Hello good People-
After a couple years of neglecting updates I have decided to give it a try.
I have an older MPC motherboard that doesn't like switching into the BIOS setup <F2> or booting off of USB as it has a utility for loading off the Ethernet or some other cabled nonsense.
After digging around I found some DVD+R's and burned the ISO to disk with the native Win10 utility.
All seems well, got it to run Live and then the Latency test with 2 sessions of glxgears expanded and going 59FPS.
Jitters are 580xx ns for Servo and 89xx ns for Base.
Then I ran the SIM-AXIS config and test program with no issues.

So...my hardware is super basic: a Gekko G540 running a small XYZ gantry with NEMA23's and bass-akward limit switches for the hard stops. I am not controlling any additional functions like spindle speed or coolant. I hope to redo the limit switches so I can find each axis' home via a switch and gang the opposite limits to a general fault.

Is it better to copy 2.5.x setup files and make the edits as discussed elsewhere on the forum or take the time to redo Stepconfig within 2.7.x?

Also, the current hard drive is dual boot between Win7 and Ubuntu 10.04. I am a stranger in a strange land when it comes to Linux.
From the voices of experience, it is worth liberating the Windows partition and replacing it with Wheezy+LinuxCNC or better to get another hard drive and keep the old one in its current configuration? I don't use the Windows side since I have another PC I prefer for that. I can't recall the size of the drive but I know it's not overly large.

Thanks in advance and Happy Holidays!

Attachment above was a project ran on the mill this time a year or two ago approx. 12" [305mm] diameter.

The screensaver cut in and pushed my jitters to 15k ns for Servo and 25k ns for Base.

Thanks John. I suppose some of these questions are 'solves some problems, causes others' type questions.

The drive in question is 80G
There is a 2G boot and a 2G Linux-swap partition
The Windows partition is 40 G with 32G used 8G free
The Ubuntu partition is 30G with 5 used 25G free
There is 126M in 3 unallocated blocks

-Can the swap partition be shared between installs?
-Would it suffice to make a 20G partition for Wheezy and throttle Lucid back to 10G?

Thanks!