Hi Lara,
I was all set to say I like the second red center. Warmth through out the block..... But when you grouped the green center with the other blocks in the grouping, the green carries the theme through nicely.
At this point I think you are probably "over-thinking" it. Either is better than the original (which was pretty good). Starting Sunday you'll have a new block to begin work on. lol Its all fun!
hugs, Jupiter