I’m not sure if this would help – but I would recommend doing the sides first and then the top – you can hide the join if its too obvious with the second tier.
What a beauty it will be when it’s finished! Its good to do these things to challenge ourselves and remember, usually, we’re our own worst critics :)
I hope she has a lovely wedding day!
Greens Yard Bakery, http://www.greensyardbakery.co.uk