DUOv1 Upgrade from 1Tb to 2Tb

Hi,

My situation is as follows:
I have a DUOv1 with 2x1Tb disks in it (on the HCL) at about 85% capacity.
X-Raid is configured and they mirror each other fine.
I have had about 5 years of faultless performance from my box but about 2 days ago I got some error messages from the NAS that disk 2 was experiencing SMART failures and that it should be replaced.
I've gone a purchased 2x2Tb disks (from the HCL)

I've done a bit of searching etc and think I understand what to do but can someone just confirm the steps to expand for me:

Backup my data
Leave the NAS going
Remove one of the disks I'd like to take disk 2 out first - which one is this, left or right as I look at the NAS from infront?
Place the new 2Tb drive into that bay and allow a resync to occur which will take hours
Wait for until volume information shows a "resync successful" message and at this point I should have a healthy 1Tb volume?
Replace the second 1Tb disk with a new 2Tb one
NAS will do another resync and will automatically resize the volume to 2Tb?

Thanks,

Kenilik