We love these window candles but were alway baffled by how the suction cup could actually attach to a window in our old house with wide wooden frames. I designed this small support bracket to solve that problem.

Print it upside down for support-free printing. If it's too tall for your window just use the cut function. If it's too short, a non-uniform scale in the Z direction should do the trick.

This thing balances so well I don't need any kind of adhesive or attachment - your mileage may vary.