I have been wracking my brains when the answer was right in front of my face.... Stencil!! That's right!! Stencil !!. The age old concept of making one and using it to make the others!!
Flower Shower as an example. You can find the tutorial here.
You can measure and use same length strips to ensure that the petals are of the same size.
If you need to apply glue to the same area repeatedly, allow to dry before you apply glue again to prevent the strip from tearing.