Your drawing shows a small tree/large shrub - look at options so designated. In local public gardens and at independent garden centers, where you can get a feel for what you think of how they look, what kind of character they have by viewing examples in person.

What kind of acacia are you looking at? we have the green southwest sweet acacia that has showy yellow flowers but also thorns and pods unless you find up the podless variety.

we also have three australian acacias two of which stay small. Mulga, A. Aneura is quite silvery with an upright spreading branch structure and A. Jennerae is greener with a more willowy look to it. I love them all!

Thanks so much for the ideas!