Like a flying painting. What I have seen most is silk paintings, but it will be very troublesome to mount them. But as far as this painting is concerned, oil painting will be better. As for the problem that oil paintings are not easy to clean, I am not a professional and I don't know how to avoid this problem. I'm really sorry!
Size. . 75-80 cm high and 45-50 cm wide.
I don't know if you want to hang it at home or in the shop. . . But it's better to have narrow walls.
Also, if it is a picture frame, I suggest you use a light-colored picture frame. Personally, I think a gold border would be better.
I hope my personal opinion will help you.