[CentOS] Upgrade to new drives in raid, larger

Hi all,

As part of my raid experience, I have yet to have to do this, but was
wondering how you guys would attempt it.

I have 3 drives in a raid 1, with one as a hot spare.
They are 250gb with all space used by two raid devices, 1 with boot, the
other with LVMs filling them up.

Now, lets say down the road I want to put in 500gb drives and replace
them....yikes.

I was thinking of taking out the spare and replacing it first. Then cloning
the raid 1 array drive as I normally would. This would leave 250 gb open.

Then I was thinking to make it a spare and then pulling out drive 2 so drive
3, the 500gb, starts syncing.
And replacing drive 2 as I did drive 3 above. When drive 3 is done syncing
then I can pull out drive 1 and allow drive 2 to sync while drive 1 is
turned into a hot spare.

Now, supposing this will work, can the raid device be enlarged easily so the
LVMs can be increased as needed (make the second raid fill up the drive as
it does now)?

Or is there a  simpler or harder way to do this without waiting forever for
the syncing.

I am thinking by the time I need to replace them, centos6 will be out and I
will just have to redo the whole computer anyway, but I have not seen anyone
talk about this, thought I would see what you gurus would do.

Bob