My centrepiece's nearly made me rip my hair out as well Danielle lol, glad I've eventually got them sorted.
I think it could work, but I agree with MummyMay on the idea of getting atleast one to try it out first, I'm only saying that because what you have in your head may not look right when you see it.
My original plan changed completely when I looked at it as I thought I had too much stuff going on and I've had to organise it about 3/4 times to get it right.
I think your idea could look pretty cute with some bow's and such on them. Are they big topiary trees?