Software RAID-1 and cloning to new and identical system

I have a voip phone system (centos) with the drives in a software RAID-1 (/md0 and /md2). I want to build a backup system with the exact same hardware so that in the event the production system goes down I can swap the new build in place and keep my phones up.

I want to dd the two drives from the production box (192.168.1.1) to the spare box (192.168.1.50). Can I simply:

dd if=/dev/md0 bs=16M | gzip -1 | nc 192.168.1.50 -p 7777

on the production, and on the spare:

nc -l -p 7777 | gzip -d | dd of=/dev/sda bs=16M

and then repeat for /md2

Would this work or is the fact that the source drives are in a software raid going to create some problems?

If it's a raid1, just pull one of the drives and put it in the backup, then add the remaining drives to each machine, as if you were replacing a failed drive. Instant clone.

That would work if it were a hardware RAID that would automatically start rebuilding the array when a new drive was swapped in, but it's software raid and it won't do that. Even though the drives are in RAID-1, they are different (ie, one shows as having 45% free space and the other shows somethign like 38%). I tried pulling 1 drive at a time and it will only boot when /md0 is the drive attached, I believe because that is the only drive with grub installed.

There is probably a way to rebuild the array from the terminal, but that is beyond me...