Question on expanding zpool ( raidz1 )

I have a 12 bay server I put freenas on. I think I just messed up expanding my storage. I currently have 8 drives now which are 2 sets of raidz1-0 and raidz1-2

I just added 3 more drives and extended my previous volume with the three drives I just purchased. I am thinking I messed up and should have waited till I bought the 4th drive.

Can I remove these three drives and re-do the extension ? I am assuming I can't extend my raidz1-3 listed below and add the 4th drive now ? I have a 11TB in...

Question on expanding zpool ( raidz1 )