I didn't come up with this idea, nor did I come up with the basic recipe either. I saw it on other boards and wanted to make one of my own.
Most of these conversions take the movie figure of Shuri and upgrade her to full Marvel Legends style by putting the base figure's head and arms onto Okoye's BAF torso and legs. I couldn't find Okoye's legs (well, one of them) at a resonable price, so I took X-23 and used her legs, painting over the half stripe on her jeans (leggings?). I also painted over the bronze tone on Okoye's armor with black, just to be different from her and Nakia's.
Using X-23's legs allows Shuri to be a bit shorter, albeit not movie accurate, but it further gives the idea that she's a teenager.