lucky wheel center circle and other problem

Hello,

How can I set the size of the circle in the middle of the wheel? It’s covering the texts on the slices.

My another problem, is when I open the website the Lucky Wheel is appearing for a fraction of a second and then immediately vanishing, while the site is downloading.

Then when I go to close the window, It appears again (this is what is set in the settings), so it’s working ok in this case.