Basing figures and busts to make them look their best can be tricky, and expensive! For years I was like, "Oh, it's finished, I gotta find a bit of timber to glue it to..." These days I'm the opposite. I won't even start a figure unless I know I can 'base it' well. Proportion is important, as Nap rightly says. A piece hanging over a base is fraught with danger. Thing is, you don't want 'dead space', which is the enemy of a good figure. And we've all seen a horror show of a figure on a base that Michaelangelo would be proud of!